• Preheat your air fryer to 300°F or oven to 350°F. Line muffin tins with cupcake liners.
• In a stand mixer, beat softened butter and sugar until smooth and creamy. Add eggs, sour cream, milk, and vanilla, mixing well and scraping down the sides.
• Gradually add flour, baking powder, baking soda, and salt. Mix until just combined, then beat on medium speed for 1 minute.
• Scoop batter into liners, filling them ½ to ⅔ full. Bake in batches (air fryer) or all at once (oven) until the centers are set.
• Cool the cupcakes completely before frosting.

Frosting Instructions

• For the frosting, beat softened butter with half the powdered sugar, vanilla, and salt until smooth. Add the remaining sugar and milk, then beat for 2–3 minutes until fluffy.
• Divide the frosting into three bowls. Tint one bowl red, one blue, and leave the third white.
• Pipe the frosting in rings onto the cooled cupcakes: blue on the outer edge, white in the middle, and red in the center. Sprinkle with silver star sprinkles.

Make Ahead & Storage

• Cupcakes can be baked a day ahead and frosted just before serving. Store frosted cupcakes in an airtight container in the fridge for up to 3 days, bringing them to room temperature before serving.
• Unfrosted cupcakes can be frozen for up to 1 month. For sharper frosting lines, chill piping bags for 10–15 minutes.

Flavor & Conversion

• For smoother batter, use room temperature ingredients. Gel food coloring provides vibrant shades without altering frosting texture.
• These cupcakes can be converted to a 9x13 cake, adjusting baking time to 30–35 minutes. Flavor variations include adding citrus zest or almond extract to the batter.

Serving Suggestions

• Serve these festive cupcakes with unlit sparklers or festive toppers. They pair well with vanilla or berry ice cream, lemonade, or fruit punch.

Holiday Adaptation

• Adapt the color theme for other holidays, such as pastels for Easter or green and red for Christmas.