Preheat the oven to 350°F/180°c. Line a 12 hole muffin tin with paper muffin liners and set aside.
Add the flour, sugar, baking powder and baking soda to a large mixing bowl. Mix until well combined and set aside.
2.5 cups all purpose flour, 1 cup sugar, 1 teaspoon baking soda, 1 teaspoon baking powder
In a separate bowl beat the softened butter, eggs, orange juice, orange zest, and vanilla until smooth with no lumps. Pour the orange batter into the large mixing bowl with the flour mixture and mix until just combined.
½ cup unsalted butter, 2 egg, ⅓ cup orange juice, 1 tablespoon orange zest, 1 teaspoon vanilla extract
Fold in the chocolate chips until evenly distributed.
1 cup dark chocolate chips
Divide the muffin batter between the muffin tin. Bake the muffins for 20-25 minutes, or until lightly golden and cooked through. Remove from the oven and allow to cool in the muffin tin for about 10 minutes before removing and transferring to a wire rack to cool completely.
For the glaze mix the powdered sugar, orange juice and vanilla in a small bowl until it is smooth with no lumps.
1 cup powdered sugar, 2 tablespoons orange juice, 1 teaspoon vanilla extract
Once the muffins have cooled, dip the tops into the orange glze, and transfer back to the wire rack. Allow the glaze to set for about 5 minutes before serving.