Preheat oven to 425°F. Grease both a sheet pan and 9×13 casserole dish with neutral oil. Set aside.

Spread the diced veggies on the greased sheet pan. Toss with the olive oil, salt and pepper, to taste. Bake the veggies for about 20-22 minutes, stirring occasionally, until they are tender and starting to brown on the edges.

During the last couple minutes of cooking, stir the spinach and garlic into to the roasted veggies. Cook until the spinach is wilted, 1-2 minutes. Remove the veggies from the oven and let them cool at room temperature for a few minutes while you prepare the rest of the ingredients. Then, decrease the oven to 350°F if you are baking the casserole right away.

Next, whisk the eggs, milk, and pesto together in a medium bowl until smooth. Season with salt and pepper, to taste. Set aside.

Grate the potatoes with a cheese grater. Spread the shredded potatoes evenly along the bottom of the prepared casserole dish followed by the veggies. Sprinkle half the cheese over the veggies. Next, pour the whisked eggs over the potato-veggie mixture. Sprinkle the remaining cheese over the top.

Bake the casserole for 40-50 minutes until the edges are golden brown and the center no longer jiggles when you give it a little shake**. Allow the casserole cool for about 5 minutes on the counter. Sprinkle fresh basil and Parmesan over the top if desired. Then, cut into 12 slices. Enjoy with hot sauce!

To make the recipe a day in advance: after you assemble the casserole, cover it with a lid or plastic wrap. Store in the fridge overnight. When you’re ready to bake the casserole, remove the lid or plastic wrap and bake at 350°F for 40-50 minutes.