Preheat the oven to 350°F. Line a muffin tin with paper liners.
In a large bowl, combine the dry ingredients: all purpose flour, whole wheat flour, ground flaxseed, sugar, baking powder, and baking soda.
Wash and scrub one lemon. Grate the outside peel using a cheese grater. Slice it in half then squeeze out the lemon juice (Save a bit of lemon zest for topping if desired)
Add milk and lemon juice to a bowl. Mix together and let sit for 1 minute to sour.
Add sour milk to a medium bowl along with egg, cooking oil and grated lemon rind. Mix together.
Add half of the flour mixture to the bowl and stir in.
Add the other half and stir in until just combined.
Gently fold in the blueberries with a rubber spatula until just combined. Do not overmix.
Divide the batter into a muffin pan lined with paper cupcake liners. Top with more lemon zest and extra blueberries. Bake for 20-25 minutes (I baked 21 mins) or until a toothpick comes out clean when poked through the center. Let cool 10 minutes then transfer to a wire rack to cool completely.
Recipe Notes:
Muffins can be stored in an airtight container in fridge or on counter for up to 1 week. These muffins can also be frozen for up to 3 months.
Batter can be mixed by hand or by using a hand mixer.
Use a cookie scoop or ice cream scoop to help divide the batter between muffin liners. This makes it easier to transfer the sticky batter and divide it evenly.
Use fresh blueberries if you can. Frozen blueberries are trickier – they tend to turn the batter a dark purple-ish color.
Use an organic lemon if possible. There will be fewer pesticides on the outer peel that you’ll be using in the recipe. You will still need to wash and scrub the lemon before using it.
Feel free to use any type of sugar that you prefer. I used coconut sugar but you can also use brown sugar ormonk fruit sweetener(it’s sugar-free).
Sprinkle a bit of extra lemon zest on the tops of the muffins just before baking. It looks lovely!