Preheat the oven to 180°C (350°F). Line a muffin tin with cupcake liners.
In a mixing bowl, sift together the flour, cocoa powder, baking powder, baking soda, and salt.
In another bowl, whisk the eggs and sugar together until well combined and slightly pale.
Add the vegetable oil, milk, and vanilla extract to the egg mixture. Mix until smooth.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
Fold in the chocolate chips.
Divide the batter evenly among the cupcake liners, filling each about 2/3 full.
Bake in the preheated oven for about 18-20 minutes or until a toothpick inserted into the centre comes out clean.
Remove the cupcakes from the oven and let them cool in the tin for a few minutes before transferring to a wire rack to cool completely.
For the frosting, beat the softened butter until creamy and smooth.
Gradually add the powdered sugar and cocoa powder, mixing until well incorporated.
Add the milk and vanilla extract, and continue to beat until the frosting is light and fluffy.
Once the cupcakes are completely cooled, pipe or spread the frosting onto the cupcakes.
You can garnish with extra chocolate chips, sprinkles, or any desired toppings.
