Remove the outer leaves of the cabbage and cut it into even wedges.
In a bowl, whisk together olive oil, garlic, lemon juice, red pepper flakes, salt, and pepper. Brush the mixture on both sides of each cabbage wedge.
Place the cabbage wedges on the prepared baking sheet. Roast in the oven for about 30-40 minutes, flipping halfway through, until the edges are crisp and the cabbage is tender.