I describe these Lemon Protein Bars as a cross between lemon cake and a lemon brownie, with one exception- they are good for you!
These are the best homemade lemon protein bars! They're perfectly sweet and tangy with a texture that's a cross between cake and brownies.
They are made with wholesome ingredients and, unlike store-bought protein bars, contain no weird additives.
The best part is that they're super easy to make, and everything is mixed by hand. Now, let's talk about ingredients.
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Ingredients and Substitutions
- Oat Flour- Oat Flour – You can buy oat flour at most supermarkets, or you can make your own by blending old-fashioned oats in a blender until the oats become a fine powder (about 30 seconds to a minute). Store it in an air-tight container for up to six months. If you’re new to oat flour, check out my Ultimate Guide to Baking with Oat Flour for tips and substitutions.
- Vanilla Protein Powder- I used Orgain Simple Creamy Vanilla Protein Powder, which is plant-based. Feel free to substitute any plant-based vanilla protein powder, although I can't guarantee the exact results unless you use that specific one. Plant-based protein powders are more absorbent than whey, so if you choose to substitute a vanilla whey protein powder, it will most likely affect the texture and baking time.
- Maple Syrup- You can substitute your favorite liquid sweetener, such as honey. A sugar-free liquid sweetener works, too.
How to make lemon protein bars
Homemade protein bars are easier to make than you might think! Follow these instructions.
- Preheat the oven to 350ºF. Grease an 8-inch square baking pan and line it with parchment paper. Grease the parchment paper and set it aside.
- Whisk the oat flour, protein powder, cornstarch, baking powder, and salt together in a large bowl. Set aside.
- In a medium-sized bowl, mash the banana using a fork or masher until no large lumps remain. Whisk in the eggs, maple syrup, lemon juice, lemon zest, and melted butter with the banana.
- Pour the wet mixture into the dry mixture and whisk until everything is well incorporated.
- Pour the batter into the prepared baking pan and bake for 19-21 minutes or until a toothpick inserted into the center comes out clean (or with a few moist crumbs).
- Allow the bars to cool for 10 minutes in the pan, then transfer the bars to a wire rack to cool completely.
- Dust with confectioners' sugar if desired and cut into 12 squares. Enjoy!
FAQs
Yes, these protein bars can be frozen for up to 3 months. Allow the bars to cool completely, wrap each individually in plastic wrap, and place them in a freezer bag or container.
Lining your pan with parchment paper prevents your bars from sticking, and lifting the whole batch out helps with cutting clean, even squares. Here is a quick tutorial on how to line a pan with parchment paper. If you don't have parchment paper, just be sure to grease your pan well with butter or non-stick spray.
Plant-based protein powders are more absorbent than whey, so if you choose to substitute a vanilla whey protein powder, it will most likely affect the texture and baking time. If you decide to substitute whey, I suggest adding an extra tablespoon or two of oat flour and keeping a close watch on the lemon bars during the last few minutes of baking as they may need additional time.
Craving more protein treats?
Check these out:
Chocolate Banana Protein Muffins
Protein Cake (Moist & Fluffy!)
Please let me know how you like the lemon protein bars in the comments! I love to hear from you and your star ratings encourage others to give the recipe a try.
Enjoy!
Crystal
📖 Recipe
Lemon Protein Bars
Ingredients
- 1 and ¼ cups oat flour*
- ⅔ cups vanilla protein powder* Orgain Simple Creamy Vanilla
- 3 tablespoons cornstarch
- 2 teaspoons baking powder
- ¼ teaspoon salt
- 1 large banana over-ripe, mashed
- 2 large eggs
- ½ cup maple syrup*
- ⅓ cup lemon juice
- ¼ cup butter melted
- 1 teaspoon lemon zest the zest of one large or two small lemons
Instructions
- Preheat the oven to 350ºF. Grease an 8-inch square baking pan and line it with parchment paper. Grease the parchment paper and set it aside. Here is a quick tutorial on how to line your pan with parchment paper.
- Whisk the oat flour, protein powder, cornstarch, baking powder, and salt together in a large bowl. Set aside.
- In a medium size bowl , mash the banana using a fork or masher until no large lumps remain. Whisk in the eggs, maple syrup, lemon juice, lemon zest, and melted butter together with the banana.
- Pour the wet mixture into the dry mixture and whisk until everything is well incorporated.
- Pour the batter into the prepared baking pan and bake for 19-21 minutes or until a toothpick inserted into the center comes out clean (or with a few moist crumbs).
- Allow the bars to cool for 10 minutes in the pan, then transfer the bars to a wire rack to cool completely.
- Dust with confectioners' sugar if desired and cut into 12 squares. Enjoy!
Notes
- Oat Flour- You can buy oat flour at most supermarkets, or you can make your own by blending old-fashioned oats in a blender until the oats become a fine powder (about 30 seconds to a minute). Store your oat flour in an air-tight container for up to three months.
- Vanilla Protein Powder- I used Orgain Simple Creamy Vanilla Protein Powder, which is plant-based. Feel free to substitute any plant-based vanilla protein powder, although I can't guarantee the exact results unless you use that specific one. Plant-based protein powders are more absorbent than whey, so if you choose to substitute a vanilla whey protein powder, it will most likely affect the texture and baking time.
- Maple Syrup- You can substitute your favorite liquid sweetener, such as honey. A sugar-free liquid sweetener works, too.
- Store your lemon protein bars covered at room temperature for a day or in the refrigerator for up to a week. I store mine individually in the fridge so I can grab one easily.
Sophie says
I love baking with oat flour and these were so good. The lemon flavor was spot on. Thanks Crystal!
Crystal Yentzen says
I'm so happy that you like the lemon bars! Thanks for the comment.
George says
Yo these Lemon Protein bars are legit.
Toni says
Can you use all purpose flour?
Crystal Yentzen says
Yes, but you will need less. Substitute 1 cup of all-purpose flour for 1 and 1/4 oat-flour. It may affect baking time too, so keep a close watch on the bars during the last few minutes of baking time. Let me know how they turn out!
Toni says
Do you need the banana? I don’t have overly ripe ones
Crystal Yentzen says
The banana adds sweetness and moisture to the bars. If you omit the banana, you can add an extra tablespoon of butter and maple syrup. It will affect the bake time, so keep a close watch on the bars during the last few minutes of baking. The next time you have bananas that are about to go bad, peel them and store them in the freezer. They are great for recipes and stay good for up to three months. I hope that helps!
Tony says
do think you could use a lemon-flavored protein mix or will that make it too tart?
Crystal Yentzen says
It will make the lemon bars more tart, but what you can do is omit the lemon zest to help balance things. Let me know how they turn out!
Elisa says
Are they freezer friendly in case I don’t finish them ?
Crystal Yentzen says
Yes, these protein bars can be frozen for up to 3 months. Allow the bars to cool completely, wrap each individually in plastic wrap, and place them in a freezer bag or container. Enjoy!