Rich chocolate cupcakes with creamy frosting are an irresistible family dessert for birthdays and celebrations. These perfectly domed treats deliver deep chocolate satisfaction in every bite.
Preheat oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners for even heat circulation.
In a large bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt to ensure even leavening.
In a separate bowl, beat eggs and sugar until pale and thick, about 2 minutes, for a tender crumb; then blend in oil, vanilla, milk, and sour cream.
Add the dry ingredients to the wet mixture in two additions, gently folding with a spatula until just combined—do not overmix to avoid dense cupcakes.
Divide batter evenly into muffin cups (about 2/3 full each). Bake for 18–22 minutes, rotating the pan halfway for consistent doming. Cool completely before frosting.