• Poke the sweet potato with a fork and bake it in a preheated oven at 425 degrees Fahrenheit for 25 minutes.
• Once the potato is fully baked, slit it open and let it cool for 10 minutes. Remove the flesh from inside and keep it aside.
• Melt butter in a skillet and add chopped yellow onion, minced garlic and cook them for 5-10 minutes, until they are soft.
• In a bowl, mix the ground turkey, sweet potato and sage and add in the cooked onions, once they are a little cool.
• Once everything is thoroughly mixed, make four patties out of the mixture.
• Heat a cast iron skillet with oil for a few minutes and then add in the burger patties.
• Sprinkle some salt and pepper on the patties and let them cook for 5 minutes on each side. Once you insert a meat thermometer in the center, the temperature should be between 145-165 degrees Fahrenheit.
• Once the patties reach this temperature, take them off the flame and keep aside.

Assembling The Burgers

• Split the brioche buns from the centre and toast them slightly in the cast iron skillet.
• Once toasted, spread some cranberry mayo on the base on the bun.
• Top this with some fresh spinach leaves and the patty. Top it with some American cheese for added flavor and serve!