Preheat half of the grill, setting the burners to high. Generously butter the cups of a 12-cup muffin tin.
In a bowl, whisk together the flour, cornmeal, baking powder, salt and baking soda.
In another bowl, whisk the brown sugar, eggs and butter together. Add the creamed corn. Stir in the dry ingredients alternately with the buttermilk until smooth. Spoon the batter into the muffin cups.
Place the muffin tin on the side of the grill that is off. Close the lid and cook for 30 minutes, or until a toothpick inserted into the centre comes out clean. During cooking maintain a temperature of 400°F (200°C) and rotate the tin once.
Unmould the muffins. Grill the muffins over direct heat, if desired.