Preheat oven to 400 degrees F (200 degrees C).

Line or grease a 12-15 muffin tin.

In a medium bowl, whisk together the flour, sugar, cocoa, baking powder, and salt.

In a large bowl, beat together the eggs, oil, milk, vanilla, orange zest, and orange juice.

Add the dry ingredients to the wet ingredients and mix until just combined.

Fold in the chocolate chips.

Fill each muffin well with batter using an ice cream scoop.

Sprinkle the tops with a few extra chocolate chips.

Bake for 15-20 minutes, or until a toothpick inserted into the center comes out clean.

Cool on a wire rack.

Prepare the glaze by whisking together powdered sugar, orange juice, and orange zest until smooth.

Drizzle the glaze over the cooled muffins.