Preheat oven to 350°F (180°C). Spray or brush an 8-inch (20 cm) square baking pan with vegetable oil and set aside. Melt butter in skillet over medium heat. Stir in onion and cook until golden, about 20 minutes. Remove from heat. Stir in pepper; set aside to cool.
In a large mixing bowl, combine cornmeal, corn flour, flaxseed, baking powder, baking soda, xanthan gum and salt; mix to blend evenly. Stir in buttermilk, corn, eggs and honey until combined. Stir in 1 1/2 cups (375 mL) Cheddar cheese and 3/4 cup (175 mL) onion mixture into batter.
Pour batter into prepared pan and smooth top. Garnish with remaining onion mixture, remaining Cheddar cheese, and red chili pepper (if using). Bake for 35 minutes, or until golden brown around edges and a toothpick comes out clean when inserted into centre of loaf. Let cool in pan to room temperature; remove from pan and let cool completely. Store in airtight container.
DISCLAIMER. As product ingredients occasionally change, customers diagnosed with celiac disease or gluten sensitivities, or those wishing to avoid gluten-containing products, should be careful to always verify the gluten-free status of a product by checking the label and by consulting the Pocket Dictionary – Acceptability of Foods & Food Ingredients for the Gluten-Free Diet, 2012 edition, Canadian Celiac Association. The information provided is not a substitute for professional medical advice. If you have specific needs, please see your health-care provider.