Kale-Butternut Squash Gratin

Preheat oven to 375 degrees F. Coat an 8-inch-square baking dish with cooking spray.

Heat oil in a large nonstick skillet over medium-high heat. Add onion and garlic; cook, stirring often, until tender and golden, about 6 minutes. Stir in kale by the handful; cook, stirring frequently, until wilted, about 5 minutes.

Whisk 2 Tbsp. milk and flour in a small bowl. Heat the remaining milk in a small saucepan over medium heat until little bubbles form on the surface, about 3 minutes. Whisk the flour mixture into the hot milk; cook, stirring constantly, until slightly thickened, 1 to 2 minutes. Whisk in cheese, salt, cumin, nutmeg, and cayenne; cook, stirring constantly, until the cheese is melted and the sauce is thickened, 1 to 2 minutes. Stir the cheese sauce into the kale mixture.

Layer half of the squash in the prepared baking dish; top with half of the kale mixture. Repeat with the remaining squash and kale mixture. Cover with foil.

Bake the gratin until the squash pierces easily with a fork, 40 to 50 minutes.

Meanwhile, place bread in a food processor and process until it forms coarse crumbs. Melt butter in a large nonstick skillet over medium-high heat. Add the breadcrumbs; cook, stirring, until toasted, 5 to 7 minutes. Transfer to a small bowl.

Sprinkle the gratin with the toasted breadcrumbs and let stand for 20 minutes before serving.