Preheat oven to 425°.
Cut 4 (1-inch) vertical slices from a head of cabbage.
Heat 2 tspcanola oil and 1/2 tsp butter in a cast-iron skillet over medium-high heat. Add 1 cabbage steak; cook 4 minutes. Place, seared side up, on a baking sheet coated with cooking spray.
Repeat with more oil and butter and remaining cabbage.
Bake cabbage steaks at 425° for 15 to 20 minutes.