Preheat the oven to 425°F. Lightly grease a standard-size muffin pan or line with muffin cups and spray the muffin cups with cooking spray.
Beat together the butter and sugar until fluffy. Beat in the eggs. Stir in the milk and vanilla just until combined. Scrape down the bowl.
In a small bowl combine the flour, baking powder, salt. Add to the creamed mixture and mix until fully combined. Do not over mix. Stir in the chocolate chips. Add the blueberries with the flour to help the blueberries not to sink while baking.
Scoop the batter into the muffin cups to close to full. Bake muffins for about 5 minutes. Lower oven temperature to 350. Continue to bake 12-15 minutes or until a toothpick inserted into the center of one comes out clean.