Preheat oven to 350 degrees F and line a 12 cup muffin tin with cupcake liners.
In a microwave safe bowl, combine butter, coconut oil and cream cheese and melt in 30 second increments. It will look chunky, this is ok. Using a hand mixer, blend and it will start to smooth out.
Add in sour cream and confectioners sugar and beat for 1-2 minutes.
Add in 4 eggs and beat for 1-2 minutes.
Add in vanilla extract and juice of 1 lemon.
Mix all dry ingredients in a bowl and then mix into wet batter.
Fold in blueberries, being careful not to smash them.
Divide the batter among 12 muffin tins.
Cook for 20-30 minutes until tops of muffin are golden and a toothpick inserted is clean.
Let cool completely before icing.
Drizzle: combine confectioners sugar and juice of 1 lemon and mix. If you find you want it thicker or thinner, add more of one of the ingredients. Confectioners sugar for thicker and lemon juice for thinner.