Preheat the oven to 400°. Line a standard muffin pan with paper liners sprayed with vegetable spray. Set aside.
In a medium bowl, whisk together the gluten free flour, cornmeal, baking powder, baking soda, salt and brown sugar. Whisk to combine and set aside.
Crack the eggs into a large bowl and whisk briskly. Add the milk and melted butter and whisk to combine. Add the flour mixture to the egg mixture and stir until the ingredients just come together and are moist.
Add the chopped strawberries to the cornmeal batter and use a rubber spatula to fold the berries into the batter evenly. Divide the batter among the 12 muffin cups.
Mix the sugar and cinnamon together. Sprinkle the cinnamon sugar liberally over the muffins and bake for 15-18 minutes or until a cake tester comes out clean. Let the muffins rest in the pan for a few minutes before serving.