Slice the kielbasa sausage into ½-inch thick rounds and place on a cutting board.

In a medium saucepan, combine brown sugar, ketchup, Worcestershire sauce, and garlic powder. Stir until it begins to bubble gently.

Add the sliced kielbasa to the saucepan. If desired, sprinkle red pepper flakes and stir well.

Reduce the heat to low and let simmer for 20–25 minutes, stirring occasionally, until sauce thickens.

Transfer the bites to a serving dish and garnish with chopped parsley before serving warm.