Preheat oven to 375℉
Line a muffin pan with paper liners or spray with non-stick spray
In a large bowl, whisk together eggs, buttermilk, oil, and vanilla.
Stir in 1 cup sugar.
Fold in 2 cups of flour, baking powder, baking soda, and salt, until dry ingredients are just incorporated.
Measure frozen raspberries into a large measuring cup and add the ¼ cup of remaining flour, shake to coat the raspberries.
Fold raspberries into batter until just combined.
Fill prepared muffin tin ⅔ full and sprinkle 2 Tbsp of sugar evenly over the tops of the batter.
Bake in preheated oven for 22-25 minutes or until muffins are baked through.
Allow to cool in pan 2-3 minutes before transferring to a wire rack.
Serve warm or at room temperature.
Store fully cooled muffins in an airtight container.