Cheesy Cauliflower, Asparagus & Mushroom Au Gratin

Preheat the oven to 475°F and grease a rimmed baking sheet. Arrange the cauliflower florets on the greased baking sheet, and drizzle on half of the olive oil. Add salt and pepper, half of the dried parsley, and half of the lemon zest and juice. Stir the cauliflower to spread the olive oil, seasonings and lemon around. Roast the cauliflower at 475°F until fork-tender, about 25 minutes. Once done, remove the cauliflower from the oven, and let it cool slightly while you cook the other vegetables. Turn the oven off.

In a large oven-safe skillet over medium-high heat, combine the remaining halves of the oil, dried parsley and lemon zest and juice as well as the minced garlic, asparagus and mushrooms. Cook, stirring frequently, until the asparagus and mushrooms have softened slightly, about 4-5 minutes. Taste and add salt, if needed, and stir in the roasted cauliflower.

Remove from the heat, and stir in the milk and 1 cup of the Gruyere cheese until combined. Top with the remaining 1/2 cup of cheese and the breadcrumbs, if using. Place the skillet in the oven and set the broiler to low. Broil the au gratin on low until the top is golden brown, about 10 minutes. Remove it from the oven and let it cool slightly before enjoying!

Note: Feel free to use gluten-free breadcrumbs, or seasoned almond meal for the topping.