Preheat oven to 375 degrees. In a large bowl, mix together flour, sugar, baking powder, and salt. Add coconut oil, eggs, and milk, stirring until just combined. Fold in blueberries.
Scoop batter into greased muffin tin (or use baking liners). Sprinkle some sugar on top of each muffin. Bake for 20-25 minutes until toothpick inserted in middle comes out clean.
