How to Make It
Preheat oven to 350°F. Beat butter and cream cheese with a heavy-duty stand mixer on medium speed until creamy. Gradually add sugar, and beat until light and fluffy. Add eggs, 1 at a time, beating until blended after each addition. Stir in vanilla, lemon zest, and lemon juice.
Stir together flour, baking powder, baking soda, and salt in a medium bowl. Gradually add to butter mixture alternately with sour cream, beating just until blended after each addition. Gently fold in blueberries. Place 24 paper baking cups in 2 (12-cup) standard-size muffin pans; spoon batter into baking cups, filling each about two-thirds full (about 1⁄4 cup).
Bake in preheated oven until a wooden pick inserted in centers comes out clean, 22 to 25 minutes, switching pans from top rack to bottom rack after 15 minutes. Cool in pans on wire racks 5 minutes. Remove from pans to wire racks. Cool completely, about 30 minutes. Pipe or spread Strawberry Frosting onto cupcakes. Top with fresh blueberries and strawberries, if desired.