Preheat oven to 180°C (350°F) and prepare a muffin tray with cupcake liners, lightly greasing them with oil.

Sift all-purpose flour, wheat flour, wheat bran, baking powder, baking soda, cinnamon, and salt together in a bowl and whisk to combine.

In a separate bowl, beat egg and sunflower oil together until well combined.

Add vanilla extract, orange marmalade, Grand Marnier (optional), honey, and milk to the egg mixture and whisk to combine.

Pour the wet ingredients into the dry ingredients and stir until just combined, ensuring there are no lumps.

Gently fold in the grated carrots.

Spoon equal amounts of batter into the prepared muffin liners.

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

Remove the muffins from the oven and cool on a wire rack.

Serve warm with tea or store in an airtight container in the fridge.