Start by preheating your oven to 350°F (177°C). Prepare a 9-inch (23 cm) springform pan by greasing it and lining the bottom with parchment paper.

In a large mixing bowl, combine the flour, baking powder, and salt, whisking them together until they are well mixed.

In another large bowl with a paddle attachment, cream the softened butter and granulated sugar together on medium speed for about 3 to 4 minutes. Make sure to scrape down the sides and bottom of the bowl.

With the mixer on low speed, add the eggs and vanilla extract to the butter mixture, mixing until everything is well combined. Again, scrape the sides and bottom of the bowl.

Next, gradually mix in the dry ingredients and buttermilk, alternating between the two. Start with the dry ingredients, then add buttermilk, repeating this sequence until everything is almost fully combined.

Gently fold in 1 cup of the raspberries by hand using a silicone spatula or spoon, being careful not to overmix.

Pour the raspberry cake batter evenly into the prepared pan. If desired, top the batter with the remaining raspberries (2 cups) and sprinkle 1 to 2 tablespoons of sugar on top.

Bake the cake for 45 to 55 minutes, or until a toothpick inserted into the center comes out clean.

Once baked, let the cake cool in the pan for 10 to 15 minutes. Carefully remove the cake from the pan and allow it to cool for an additional 10 to 15 minutes on a wire rack.

Transfer the cooled raspberry cake to a serving plate, dust with powdered sugar, slice, and enjoy!