-Preheat oven to 350. Coat a 12 cup muffin tin with cooking spray or line with paper baking cups.
-In large bowl, beat the sugar and the margarine with a wooden spoon. Stir in the yogurt, blueberries, yellow squash puree, egg, lemon extract, and lemon zest.
-Add the flour, flaxseed meal, baking powder, baking soda, and salt. Stir just to combine, but do not over mix-batter is supposed to be lumpy.
-Divide the batter amongst the muffin cups. Bake until tops of the muffins are lightly browned and a toothpick comes out clean when inserted in the center, 13 to 16 min. Turn the muffins out onto a rack to cool.
-Store in an airtight container at room temperature for up to 2 days, or wrap individually and freeze for up to 1 month.
Check out more pictures of these BLUEberry Muffins!