Preheat your oven to 400°F (200°C) and line a 12-cup muffin tin with paper liners.

In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt. Rub the orange zest into the mixture.

In a separate medium bowl, whisk the egg, milk, vegetable oil, and juice of one large orange until smooth.

Gently pour the wet ingredients into the dry mix and fold together until just combined, being careful not to overmix.

Spoon the batter into each muffin cup, filling them about 2/3 full.

Bake for 18 to 22 minutes, checking for doneness with a toothpick that should come out clean.

While the muffins cool, prepare the glaze by mixing powdered sugar with orange juice until desired consistency.

Drizzle the orange glaze over the cooled muffins and garnish with reserved orange zest.