Preheat oven to 400°F and line a large sheet pan with parchment paper or lightly grease it.
Arrange cabbage wedges on the sheet pan and nestle sausage slices around and between them.
Drizzle olive oil over everything, then sprinkle with garlic powder, paprika, salt, pepper, and onion powder, making sure to season both sides of the cabbage wedges.
Roast for 30-35 minutes, flipping the cabbage wedges and stirring the sausage halfway through, until the cabbage is tender and golden brown at the edges and the sausage is nicely browned.
Serve immediately while hot, optionally garnishing with fresh parsley or a squeeze of lemon juice.