1Position a rack in the middle of the oven and preheat to 400°F. Spray two 12-cup muffin pans generously with cooking spray or line with paper liners.
2In a bowl, sift together the flour, baking powder, baking soda, and salt. In the bowl of a mixer fitted with the paddle attachment, on medium-high speed, beat the butter with ¾ cup of the sugar until lightened and creamy, about 2 minutes. Beat in the eggs, one at a time, then 2 teaspoons vanilla, until combined, scraping down the sides of the bowl with a rubber spatula. Add the sour cream and beat on low speed until nearly incorporated. Add the dry ingredients and, using the rubber spatula, stir just until evenly moistened. Gently stir in the diced strawberries. The batter will be thick.
3Using a 2-ounce ice cream scoop, heap the batter into the greased muffin cups (you’ll probably fill about 15), filling them 3/4 full. Bake until the muffins are golden brown and a toothpick inserted into the center of one comes out clean, about 14 minutes. Let the muffins cool in the pan on a wire rack for about 5 minutes, then unmold onto the rack. Let cool completely.
4When the muffins have cooled, in the bowl of a mixer fitted with the whip attachment, on medium-high speed, beat the cream, remaining 2 tablespoons of sugar, and remaining 1 teaspoon of vanilla to medium-stiff peaks. Do not overbeat. Dollop or pipe some cream on top of each muffin, top with a strawberry, cut side down, and serve.