Preheat oven to 350°F (180°C). Spray a 9-inch enamel-coated cast-iron skillet with baking spray with flour.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter and 1 cup
(200 grams) sugar at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating well after each addition. Beat in vanilla.
In a medium bowl, whisk together flour, baking powder, and salt. Reduce mixer speed to low. Gradually add flour mixture to butter mixture alternately with sour cream, beginning and ending with flour mixture, beating just until combined after each addition. Fold in strawberries. Spread batter into prepared skillet. Sprinkle with remaining ¼ cup (50 grams) sugar.
Bake until a wooden pick inserted in center comes out clean, 35 to 40 minutes. Let cool completely on a wire rack. Serve immediately.
Notes
Add lemon or other citrus juice to strawberries to help maintain their bright color during baking.
Recipe by Bake from Scratch at https://bakefromscratch.com/strawberry-skillet-cake/