Chef John's Turkey Sloppy Joes

Melt butter in a heavy skillet over medium heat. Add onion; cook and stir until onion starts to brown about 5 minutes. Season with salt and black.

Mix ground turkey and 1/2 cup cold water into onions. Cook and stir breaking up the meat until it begins to brown about 2 minutes. Add ketchup brown sugar cayenne pepper salt and black pepper. Cook and stir until liquid is reduced about 5 minutes. Stir in Worcestershire sauce and cocoa powder. Cook stirring frequently and adding up to 1 cup water if needed until meat is cooked through and liquid is reduced and thick 20 to 30 minutes.

Preheat the oven's broiler and set the oven rack about 6 inches from the heat source. Toast hamburger buns until golden 2 to 3 minutes.

Remove turkey mixture from the heat and mix in green onions and Cheddar cheese. Serve on toasted hamburger buns.