Preheat your oven to 400°F. Spray 12-cup muffin tin with nonstick spray, or line with paper cupcake liners.
In a medium mixing bowl, whisk together the flour, sugar, baking powder and salt.
In another bowl, combine the melted butter, milk, egg and vanilla. Whisk these wet ingredients together until they’re smooth and creamy.
Gently stir the wet ingredients into the dry mixture. Be careful not to overmix; it’s okay if the batter appears a bit lumpy.
In a small bowl, toss the raspberries with ¼ cup of flour. Coating the raspberries in flour helps prevent them from sinking to the bottom of the muffins during baking.
Gently fold the floured raspberries into the batter.
Divide the batter evenly between the muffin cups.
Generously sprinkle the batter with white sugar for topping.
To add a pop of color, top each muffin with pieces of the sliced raspberries.
Place the muffin tin in the preheated oven and bake for 18 to 22 minutes.
