Preheat the oven to 350 degrees F.
Line a 9-inch springform pan (or cake pan) with parchment paper.
In a large bowl (or stand mixer), whip together the softened butter and sugar for about 4-5 minutes, until the mixture is pale yellow.
Add in the eggs one at a time, mixing well after each addition.
Mix in the vanilla.
Sift the flour, baking powder, and salt in a separate bowl.
Gradually add in the flour mixture and sour cream, alternating one at a time, beginning and ending with the flour mixture. Mix well between each addition.
Fold in the sliced strawberries.
Pour the cake batter into the pan and spread to smooth.
Sprinkle the granulated sugar topping (3 Tablespoons) evenly over the batter.
Bake for about 40-45 minutes, or until the top begins to lightly brown and a toothpick comes out clean.
Let the cake cool completely, then remove from the pan.
Dust with powdered sugar (optional), cut into slices, and enjoy!