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.