Preheat the oven to 350°F. Line a muffin or cupcake pan with paper liners.
In a large bowl, beat the butter and sugar until light and creamy, about 2 minutes. Add the eggs and vanilla to the butter mixture and beat again, scraping down the sides of the bowl as needed.
½ cup salted butter, 1 cup granulated sugar, 2 large eggs, 1 teaspoon vanilla extract
Add flour, baking powder, and salt, and mix until combined.
1½ cups all-purpose flour, 2 teaspoons baking powder, ½ teaspoon salt
Add milk, lemon juice, and lemon zest, mixing again until combined.
½ cup whole milk, 1 Tablespoon lemon zest, ¼ cup fresh lemon juice
Scoop the batter into the prepared cupcake liners, filling them about ⅔ full. I find a medium cookie scoop works best.
¾ cup raspberry jam
Bake the cupcakes for 15–18 minutes until the tops bounce back when you touch them or a toothpick inserted in the center of the cupcakes comes out clean. Cool completely.