Lemon Protein Bars – A Nostalgic Treat with a Healthy Boost
The Story Behind These Lemon Protein Bars
Growing up in Northampton, Massachusetts, weekends meant baking with my Nana. Her lemon bars were a staple—gooey, buttery, and so tart they’d make you squint. We’d laugh, dust powdered sugar everywhere, and sneak warm corners from the pan before they were fully cooled. Years later, I still chase that flavor, but now I bake a version that’s just a bit more balanced—lemon protein bars that taste like childhood but fuel like a snack.
These bars have all the brightness and bite of the classic lemon dessert, but each square packs 12 grams of protein thanks to unflavored collagen peptides. I bake them in my little dessert studio above a flower shop, where they’ve become a best-seller for folks who want something indulgent that doesn’t derail their day. Whether you need post-workout fuel or a midday boost, these lemon protein bars have you covered.
You’ll find them featured often in my Healthy Sweet Treats collection, especially when I’m preparing for events or freezer stocking. And for a cozy brunch pairing, my Cinnamon Roll Focaccia is a reader favorite too.
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Table of content
Lemon protein Bars – Zesty, Gooey & Packed with 12g Protein
Bright lemon flavor with a perfect shortbread crust, these lemon protein bars are packed with 12g of protein per square thanks to collagen.
- Prep Time: 10 minutes
- Cook Time: 30 minutes
- Total Time: 3 hours 45 minutes
- Yield: 16 bars 1x
- Category: Healthy Sweet Treats
- Method: Bake
- Cuisine: American
Ingredients
SHORTBREAD CRUST:
⅔ cup all-purpose flour
⅓ cup almond flour
⅓ cup powdered sugar
¼ tsp salt
¼ cup collagen peptides (unflavored)
⅓ cup unsalted butter, cubed
LEMON CURD:
¾ cup sugar
3 eggs + 3 egg yolks
¼ tsp salt
1 cup lemon juice
Zest from 1 lemon
3 tbsp butter
½ cup collagen peptides
¼ cup canned coconut milk
Instructions
1. Preheat oven to 350°F. Line an 8×8 pan with parchment paper.
2. Combine crust ingredients and mix with hands until crumbly like wet sand.
3. Press crust into pan and bake for 16–18 minutes until golden.
4. Whisk sugar, eggs, and yolks in cold non-reactive pan.
5. Add lemon juice and zest. Cook over low heat, stirring constantly.
6. Add butter and stir until melted, then mix in collagen until smooth.
7. Cook until thickened, 5–7 minutes. Remove from heat and stir in coconut milk.
8. Pour lemon curd over hot crust. Tap to remove air bubbles.
9. Bake 12–15 minutes until just set. Chill 1 hour on counter, 2 hours in fridge.
Notes
• Use fresh zest and bottled juice for easy prep.
• Sub butter with Miyoko’s for vegan.
• Heavy cream works if you’re out of coconut milk.
• Freeze slices individually wrapped for 3 months.
Nutrition
- Serving Size: 1 bar
- Calories: 210
- Sugar: 12g
- Sodium: 80mg
- Fat: 9g
- Saturated Fat: 4g
- Unsaturated Fat: 4g
- Trans Fat: 0g
- Carbohydrates: 20g
- Fiber: 2g
- Protein: 12g
- Cholesterol: 55mg
What Makes These Lemon Protein Bars So Special?
The secret is balance. Tangy lemon curd made with both juice and zest gives these bars a sharp, clean citrus flavor, while the crust—made with almond flour, powdered sugar, and butter—adds a soft shortbread bite. But it’s the unflavored collagen stirred into the warm curd that transforms them into lemon protein bars instead of just another dessert.
That small touch makes a big difference. The bars are creamy but firm, indulgent but satisfying. You’d never guess they’re functional. Salt enhances the brightness, and coconut milk gives a silky finish that melts on your tongue. They’re the kind of bar you’ll want in your fridge all year long—easy to slice, easy to freeze, and even easier to love. Checkout our Facebook page for more recipes.
How to Build the Perfect Lemon Protein Bars
Mastering the Shortbread Crust
The first step to perfect lemon protein bars is a crust that holds everything together without overpowering the curd. For that, we use a mix of almond flour and all-purpose flour, giving it just enough structure with a slight nutty richness. Powdered sugar keeps the texture delicate, while a pinch of salt heightens every flavor. Cold butter is key here—cut it into cubes and use your hands to rub it into the dry ingredients until the mix resembles damp sand.
The dough won’t come together like a traditional cookie base, and that’s exactly what you want. When the mixture holds together but still crumbles slightly, press it firmly into a parchment-lined 8×8 pan. I like to clip the parchment paper to the pan’s edges using binder clips so it stays in place while pressing. Use your fingers or an offset spatula to push it evenly into the corners. Bake it at 350°F for about 16 to 18 minutes until just golden.
This base gives the lemon protein bars a sturdy, melt-in-your-mouth layer that doesn’t fall apart when sliced or stored. It’s my go-to crust for many of the bars in my Healthy Baking collection, especially ones I freeze for meal prep.
Making the Protein-Packed Lemon Curd
Now the heart of these bars—the curd. Start with a cold non-reactive pan (like stainless steel or ceramic). Whisk together granulated sugar, whole eggs, and extra egg yolks until the mix becomes smooth and pale. This step is crucial: combining before the acid prevents curdling. Then add lemon juice and zest. Stir constantly over low heat—never let it boil.
Once it begins to warm, add the butter and stir until fully melted. Then add the unflavored collagen peptides. Because collagen dissolves best in warm liquid, adding it here ensures your lemon protein bars are silky smooth without any lumps. After 5 to 7 minutes of cooking, the curd thickens. Test it by running a finger through the back of a coated spoon—it should leave a clean line.
Finish by stirring in a little canned coconut milk, which adds creamy body and softens the tartness. This makes the lemon curd rich but not overly sharp. I’ve used this same curd as a filling in tartlets and layer cakes, but it really shines when paired with the buttery base of these lemon protein bars.
Next up? We’ll bake it all together and dive into how to store, freeze, and serve these protein-packed treats like a pro.
Bake, Chill, and Store Your Lemon Protein Bars Like a Pro
Bake Until the Center Gently Wiggles
Once the curd has thickened and the crust is out of the oven, pour the warm lemon curd directly over the hot shortbread base. This helps both layers fuse together, creating that signature soft, creamy bite in these lemon protein bars. Tap the pan lightly on the counter to pop any air bubbles. This small step helps keep the top glossy and smooth after baking.
Return the pan to the oven for 12 to 15 minutes. Keep a close eye—you’re looking for the filling to set around the edges but still wiggle gently in the center when you tap the pan. That “Jell-O jiggle” is your sign it’s done. Overbaking can cause the curd to become rubbery or crack, which is one of the most common reasons people ask, “Why are my lemon bars rubbery?”
After baking, let the bars cool at room temperature for an hour. Then refrigerate them for at least two more hours before slicing. Chilling firms the filling and makes clean slices possible. Plus, lemon protein bars taste even better cold—the texture becomes denser, creamier, and the flavor sharper.
Smart Storage & Freezer-Friendly Tips
These lemon protein bars are fantastic for make-ahead planning. After chilling, store them in an airtight container in the fridge for up to two weeks. They stay firm and flavorful, and because they’re made with collagen (not whey), there’s no gritty aftertaste or texture change.
Want to store them long-term? Wrap each bar tightly in plastic wrap, place in a zip-top bag or airtight container, and freeze for up to three months. Label the bag with the name and date—trust me, you’ll forget later—and you’ll always have a treat ready to go. They thaw in about 20–30 minutes at room temp or overnight in the fridge.
I often make a double batch and stash one tray in the freezer for surprise guests or a post-workout snack. The balance of tangy citrus, creamy curd, and that protein boost makes these lemon protein bars just as ideal for meal prep as they are for a casual afternoon treat.
Variations about Lemon Protein Bars
Fun Variations to Keep Things Fresh
Once you’ve mastered the base recipe, you can easily customize your lemon protein bars to match your taste or pantry. Want a berry twist? Swirl in a few spoonfuls of blueberry or raspberry jam into the curd before baking. It adds color and a fruity contrast to the lemon.
For extra texture, stir in a tablespoon of chia seeds into the curd mixture—hello, lemon poppy seed vibes. If you’re going for dairy-free, swap butter with a high-quality vegan option like Miyoko’s. And if you’re out of coconut milk, use traditional heavy cream or a thick dairy-free substitute.
These tweaks let you enjoy lemon protein bars in so many different ways, whether you’re prepping for brunch, gifting, or stocking the freezer for the week ahead. Readers who love this recipe often try my Coconut Milk Rice Pudding next—it’s rich, easy, and also freezer-friendly.
Are protein bars actually healthy?
They can be—especially when made with whole-food ingredients like almond flour, lemon, eggs, and collagen. These lemon protein bars skip fillers and use natural sources of protein, making them a nutritious snack or dessert.
Is the lemon bar Premier Protein good?
Premier Protein bars are convenient, but they’re highly processed. If you prefer fresh flavor and whole ingredients, homemade lemon protein bars offer more control over taste, texture, and nutrition.
What protein bars does Jennifer Aniston eat?
Jennifer Aniston promotes Vital Proteins collagen, which is similar to what’s used in this recipe. While she hasn’t shared a lemon bar favorite, these lemon protein bars use collagen in the same way—dissolved into warm liquids for invisible protein.
Why are my lemon bars rubbery?
Rubbery lemon bars usually mean the curd was overbaked or boiled. For soft, custard-like lemon protein bars, bake only until the center jiggles and always cook the curd gently over low heat without boiling.
Conclusion
With their zesty brightness, buttery crust, and creamy protein-packed filling, these lemon protein bars prove you don’t have to choose between indulgent and intentional. They freeze beautifully, fuel you with 12g of protein per square, and taste like something from your childhood—only better.
They’ve become a staple in my dessert studio for a reason, and I think once you try them, you’ll understand why. Make a batch, freeze half, and keep your snack game strong. And if you’re craving more citrusy inspiration, explore the Healthy Sweet Treats archive—your next favorite is waiting.
