Boil chicken breasts for 20-25 minutes or until done. (save water)
Preheat oven to 350 degrees.
When chicken breasts are cooled, shred. (I use my hand mixer to easily shred the chicken.)
Layer 1 - In 9 x 13 casserole dish, melt 1/2 stick of butter. Spread shredded chicken over melted butter. Sprinkle salt, black pepper and dried sage over this layer. Sprinkle frozen peas and corn over chicken. Do not stir.
Layer 2 - In a small bowl, mix milk and gluten-free Bisquick. Slowly pour gluten-free Bisquick mixture all over chicken. Do not stir.
Layer 3 - In a medium bowl, whisk together 1 cup of chicken broth (from your boiled chicken), chicken granules, and gluten-free cream of chicken soup. Once blended, slowly pour over the gluten-free Bisquick layer. Do not stir. (Dairy-free use my recipe for Gluten-Free Cream of Chicken Soup with dairy-free butter and milk)
Bake casserole for 45-60 minutes, or until the top is golden brown. Enjoy!
Store leftovers in an air-tight container. Re-heat in the microwave or oven.