Grilled Chicken Burger with Cranberry and Jalapeno Sauce

Instructions

1. Preheat the oven to 425 degrees Fahrenheit.
2. Season the chicken breasts and grill for about 10 to 15 minutes per side if using an outdoor grill); add the sliced onion and pepper when you have about 7 minutes to go.
3. Toast the gluten-free bun, on one-half spread over some dairy-free butter and a teaspoon of the cranberry jalapeno sauce, then top with the chicken and the rest of the sauce. 
4. Place some spinach leaves, sliced avocado (season them first with lemon juice, salt and pepper), and the grilled onion and pepper.