here's my recipe, if you wanna give it a try. i don't have lemon in it, but orange instead. it gives it a really nice flavor.
Blueberry-Oatmeal-Buttermilk muffins
2 c. pastry flour
1 c. white sugar
1 tbl baking powder
1/2 tsp salt
1 large egg, beaten
1 c. buttermilk
1/4 c. vegetable oil
1 tsp vanilla extract
2 tbl dried orange zest (1 tbl fresh)
1 1/2 c. frozen blueberries
1/2 c. brown sugar
1/4 c. flour
2 tsp cinnamon
1/4 c. softened butter
1/4 c. rolled oats
Mix together 2 c. flour, white sugar, baking powder, and salt. Make a well in the center of the mixture, and set aside. In a separate bowl, mix together the egg, buttermilk, oil, vanilla, and orange zest. pour the wet mixture into the well in your dry mixture , and slowly incorporate them together with a wooden spoon. lightly coat the blueberries in flour (to prevent them from sinking while baking) and fold into batter. Fill oiled or lined muffin pans 2/3 full.
in a small bowl, combine brown sugar, flour, cinnamon, softened butter, and oats. with the back of a fork, combine ingredients into the softened butter. crumble the streusel onto each muffin. bake in a 350F oven for about 25 minutes.
enjoy!