*If you want the prettiest looking muffins, use fresh blueberries. They won't "bleed" blue/purple into your batter creating streaks. But, if you are using frozen blueberries, minimize the streaks by tossing the 1 cup blueberries with and additional 1 tablespoon tapioca flour. This coating also helps them from sinking to the bottom of the batter. Then, very gently stir in the flour coated frozen berries into batter. This will result in less blue streaks from the frozen blueberries.
**For subtle lemon flavor or if you don't have lemon extract, use just lemon extract OR vanilla extract + lemon zest as written. If you love lemon flavor like I do, use both lemon extract and the zest of one lemon.
NUT-FREE VARIATION - Instead of the almond flour + tapioca/arrowroot flour use ONLY 3/4 cup cassava flour + an additional 1/4 cup oil. This will yield slightly less batter but the right consistency.