Peanut Butter & Jelly Cupcakes

Name: Peanut Butter & Jelly Cupcakes
Prep time: 35 min
Cook time: 22 min
Total time: 57 min
Cuisine: American
Ingredients: 1 and 3/4 cups (207g) cake flour* (spooned & leveled); 3/4 teaspoon baking powder; 1/4 teaspoon baking soda; 1/4 teaspoon salt; 1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature; 1 cup (200g) granulated sugar; 3 large egg whites, at room temperature; 2 teaspoons pure vanilla extract*; optional: seeds scraped from 1/2 of a vanilla bean; 1/2 cup (120g) full-fat sour cream*; 1/2 cup (120ml) whole milk*; about 1/4 cup your favorite jelly (any flavor!); 5 Tablespoons (71g) unsalted butter, softened to room temperature; 1 cup (250g) creamy peanut butter; 1 cup (120g) confectioners’ sugar; 1/3 cup (80ml) heavy cream; 1 teaspoon pure vanilla extract; ¼ teaspoon salt; optional: crushed peanuts for topping