Hands down, the best appetizer ever!

Preheat your oven to 375°F (190°C).
Cook the ground sausage in a skillet until browned and fully cooked. Drain excess fat.
Combine the cooked sausage, cheddar cheese, green onions, Parmesan cheese, and black pepper in a bowl.
Place a wonton wrapper on a clean, flat surface.
Spoon a teaspoon of the sausage mixture into the center of the wrapper.
Moisten the edges of the wrapper with water and fold it over to form a triangle, pressing the edges together to seal.
Repeat with the remaining wrappers and filling.
Arrange the filled wontons on a baking sheet lined with parchment paper.
Brush the wontons with olive oil or melted butter.
Bake in the preheated oven for 10-12 minutes, or until golden brown and crispy.
Let cool slightly before serving.