Preheat the oven to 350°F.

Spray a 9-inch round cake pan with cooking spray.

Using a stand mixer or hand mixer, cream the butter and 1 cup of granulated sugar on medium speed for 2–3 minutes, until light and fluffy.

In a separate medium bowl, mix the flour, baking powder, and salt.

Add the eggs, vanilla, and zest to the bowl of the stand mixer, and combine well.

Gradually add half of the flour mixture with half of the sour cream, repeating with the remaining flour mixture and sour cream. Mix until combined, scraping down the sides of the bowl as needed.

Gently fold in the berries with a spatula so they don’t break.

Spread the batter in the pan evenly.

Sprinkle the remaining sugar over the batter, then pour boiling water over the entire cake.

Bake the cake for 35-40 minutes, until the top is cracked and slightly brown, and the center is barely jiggly.

Let the cake cool completely before slicing and serving.