Preheat oven to 375°. Line 24 standard muffin cups with paper liners.
Whisk together flour, baking powder, and salt. Set aside.
Using an electric mixer on medium-high speed, beat butter, sugar, and brown sugar until pale and fluffy. Add eggs, one at a time, mixing well after each addition. Mix in vanilla.
Reduce mixer speed to low. Add flour in two batches, alternating with milk. Stir in chocolate chunks.
Spoon 1/4 cup batter into each muffin cup. Bake 20 minutes, or until cupcakes are pale golden and a toothpick inserted in the center comes out clean. Transfer cupcakes to wire racks to cool.
Makes about 2 dozen cupcakes.