Preheat oven to 425°F (218°C). Line a 12-count muffin tin with muffin liners or grease with nonstick spray. Set aside.
In a large bowl, whisk together the flour, baking powder, and salt. Set aside.
In another bowl or stand mixer, beat the room temperature butter, granulated sugar, and brown sugar until smooth and fluffy on medium speed, about 2–3 minutes.
Beat in the eggs. Add the milk and vanilla extract, mixing until fully combined.
Slowly add the dry ingredients to the wet ingredients, mixing on low until just combined. The batter will be thick and creamy. Be sure not to overmix your batter.
Fold in the blueberries and chocolate chips with a spatula.
Divide the batter evenly between the 12 muffin cups, filling each almost to the top. Sprinkle with coarse sugar for a crunchy top.
Bake for 5 minutes at 425°F, then (without opening the oven) reduce the oven temperature to 350°F and bake for an additional 18–22 minutes or until a toothpick inserted in the center comes out clean.
Cool in the pan for 5 minutes, then transfer muffins to a wire rack to cool completely.