01 -
Preheat the oven to 350°F (177°C). Line a 12-cup muffin pan with cupcake liners.
02 -
Whisk the flour, baking powder, and salt together in a large bowl and set aside.
03 -
Using a handheld or stand mixer fitted with a paddle attachment, beat the butter, sugar, and lemon zest together on medium-high speed in a large bowl until creamy, about 2 minutes. Scrape down the sides and bottom of the bowl as needed.
04 -
Add eggs and vanilla extract, then beat on medium-high speed until combined, about 1 minute. Scrape down the sides again.
05 -
Add the dry ingredients, then with the mixer on low speed, slowly pour in the milk and lemon juice. Mix until just combined, being careful not to overmix.
06 -
Divide the batter evenly among the liners and bake for 18–21 minutes, or until a toothpick inserted into the center comes out clean. Allow to cool completely before filling and frosting.
07 -
Using a sharp knife, cut a circle into the center of the cooled cupcakes to create a pocket about 1 inch deep. Fill each pocket with raspberry jam, using a teaspoon to fit 1–2 teaspoons per cupcake.
08 -
Replace the top of the removed cupcake piece over the jam-filled hole.
09 -
Beat softened butter on medium speed for 3-4 minutes until smooth and creamy. Add confectioners’ sugar, raspberry jam, milk, vanilla extract, lemon juice, and salt. Start mixing on low speed, then increase to high speed for 1 minute until combined.
10 -
Frost the cooled cupcakes with the raspberry buttercream using a piping tip like Wilton 1M, and garnish with a fresh raspberry and lemon slice if desired.
11 -
Refrigerate the cupcakes for at least 1 hour before serving to set the frosting.