Prep. Preheat oven to 375 F and line a muffin tin pan with muffin liners.
Mix. Combine the dry ingredients in a medium bowl. In a large bowl, use an electric mixer to combine almond milk (2 tablespoons), eggs (2), vanilla extract (1 teaspoon), and unsalted butter (2 tablespoons). Add the dry ingredients and combine using the electric mixer, occasionally scraping down the sides to fully incorporate everything. Stir in blueberries (1/2 cup) and lemon zest (if using) with a rubber spatula.
Bake. Spoon batter into prepared muffin pan. (Craving a streusel topping? Check out note 5). Bake in preheated oven for 24-26 minutes. Enjoy!
The flour - Opt for a fine grain almond flour such as Bob's Red Mill, Trader Joe's, or Costco brands.
The protein powder - this recipe has only been tested using ISO Pure whey protein isolate. Protein powder is used to add fluff to these muffins. Know that different products will vary in how much "fluff" they add.
The psyllium husk - If you'd prefer, use psyllium husk instead of protein powder, and add 2 additional tablespoons of almond milk. NOTE: I prefer protein powder here, as it makes the batter more cake-like, and less moist.
The sweetener - This recipe was measured using Lakanto or Swerve. If using a different brand of erythritol (or allulose) know that they're 70% as sweet as the products mentioned.
Add a streusel - 1/4 cup Swerve/Lakanto+ 1/4 cup walnuts/pecans + 1/2 teaspoon cinnamon. Toss together in a bowl, sprinkle on top, and press lightly to adhere.