Leek and Greens Gratin

Heat ¼ cup olive oil in your largest skillet or heavy-bottomed pot over medium–high heat. Add leeks and season with salt and pepper. Cook, stirring occasionally until the leeks are bright green and totally tender, almost melty, 10–15 minutes (they shouldn’t get any color, but if they do, that’s okay).

Working with one handful at a time, add some kale and season with salt and pepper. Stir and let wilt between additions, repeating until you’ve added all the kale and it’s nice and wilted, 5–8 minutes.

Add crushed red pepper flakes if using, followed by heavy cream. Let the cream bubble up around the edges and use a spatula to scrape up any brown bits that may have formed while cooking the leeks and kale. Remove from heat, stir in the cheese, and transfer everything to a 2-quart baking dish (you can do this part ahead of time, even a day or two; just cover and refrigerate until ready to top with bread crumbs and bake).

When ready to bake, preheat oven to 425°. Combine bread crumbs and remaining 2 tablespoons olive oil in a medium bowl. Season with salt and pepper and toss until crumbs are thoroughly saturated and evenly mixed. Scatter over leek and greens and bake until bread crumbs are golden brown and everything below is bubbling nicely around the edges, 15–20 minutes. Remove from oven and serve.