Parsnip and carrot ribbons sub in for noodles in this cheesy baked casserole. If you’re never made sauce mornay, it’s simple a béchamel sauce with cheese stirred in for flavor. A side arugula salad offsets all that creamy richness with a refreshing bite.

Make the béchamel sauce: heat 2 tablespoons butter in a medium oven-proof pan over medium heat. Add the onion to the pan and cook, stirring constantly, 3-4 minutes, until softened. Add half the thyme to the pan and cook 30 seconds, until fragrant. Whisk the flour into the onion mixture and cook, whisking constantly, for 1 minute. Slowly (1/4 cup at a time) whisk in the milk, stirring to incorporate between each addition. Bring to a boil, whisking constantly, until thickened. Reduce to a simmer and season with salt and pepper.

Preheat broiler to high or oven to 500 degrees. Add the carrot and parsnips to the pan and toss to coat in the béchamel sauce. Simmer for 7-10 minutes, until carrots and parsnips are al dente and sauce has thickened. Taste and season with salt and pepper, if necessary.

Make the breadcrumb topping: meanwhile, combine in a small bowl the panko, Parmesan, and the remaining thyme. Season with salt and pepper. HINT: For a super crispy topping, add a drizzle of olive oil.

Remove the pan from the heat and stir in the gruyere cheese. If you do not have an oven-proof pan, transfer mixture to a small baking dish. Top with the breadcrumb topping and place pan under the broiler for 2-3 minutes, until golden brown.

Dress the arugula: in a medium bowl, toss together the arugula, a squeeze of lemon, and 1 tablespoon olive oil. Season with salt and pepper.

Serve the parsnip and carrot gratin divided between plates, with the salad to the side. Enjoy!