6tablespoons(3/4 stick) unsalted butter, room temperature
1teaspoonfinely grated lemon zest
2apricots, halved, pitted, cut into 1/4-inch wedges
Preheat oven to 350°. Coat muffin cups or pie pan with nonstick spray. Whisk flour, baking powder, and salt in a medium bowl.
Using an electric mixer, beat butter and sugar in another medium bowl, occasionally scraping down sides of bowl, until light and fluffy, about 2 minutes. Add egg, lemon zest, and vanilla and beat until combined.
With mixer on low speed, add dry ingredients in 3 additions alternately with milk in 2 additions, beginning and ending with dry ingredients. Divide batter among muffin cups (cups will be only 1/3 full) and smooth tops. Or spread it out in the pie pan. Top with apricot slices and sprinkle with raw sugar.
Bake until cakes are golden and a tester inserted into the centers comes out clean, 20–25 minutes or more like 30-35 for a cake. Transfer pan to a wire rack; let pan cool 5 minutes. Transfer cakes to rack and let cool completely.