I love cooking, but I hate doing dishes, especially pots and pans. This casserole comes together in a large skillet that transitions from stovetop to oven, making cleanup a breeze. I like to use a well-seasoned cast-iron skillet, but a Dutch oven would also work well here.
This earthy, one-pan dish has a woodsy, almost smoky flavor thanks to gruyere and fresh sage. Thickening the sauce with cornstarch gives it a silky mouthfeel and is less fussy than making a béchamel with flour.
Pro Tip: For a gourmet touch, make fried sage leaves for garnish. Heat 1/4 cup of olive oil in a small skillet over medium-high heat. When hot, add whole sage leaves, 2-3 at a time and fry for 20 seconds. Remove promptly and sprinkle with sea salt.