Preheat the oven to 375°F. Spray a 12-cup muffin tin with nonstick spray.
In a medium bowl, whisk together the flour, sugar, baking powder, baking soda and salt.
In a separate bowl, whisk together the eggs, oil, buttermilk, sour cream and vanilla. Add to the dry ingredients, stirring just until moistened. Gently stir in 1½ cups raspberries.
Spoon the batter into the prepared muffin tin, filling each cup about ¾ full. Add the remaining ¼ cup halved raspberries to the tops of the batter. Sprinkle sugar on top of each. Bake 20 to 25 minutes, or until golden and a toothpick inserted into the center of a muffin comes out clean. Serve warm!