Trust us: once you try grilling cheese, you’ll want to find a way to put it in everything. Thanks to its high melting point, the cheese stays firm when you fry it in a pan. Plus, the heat only heightens its salty and savory qualities. Next to a brightly colored jumble of veggies, it feels positively rapturous, delivering bites of cheesy goodness in between bursts of tomato, creamy avocado, sweet potato, and herbs.
Adjust rack to middle position and preheat oven to 425 degrees. Wash and dry all produce. Peel sweet potatoes, then dice into ½-inch pieces. Halve and peel onion, then cut into ½-inch wedges.
Toss sweet potatoes and onion on a baking sheet with a drizzle of olive oil and a pinch of salt and pepper. Roast, tossing halfway through, until browned and tender, about 25 minutes.
Meanwhile, halve tomatoes. Finely chop cilantro; place 1 TBSP in a large bowl and set aside. Mince garlic until you have 1 tsp (you may have a clove left over). Halve lemon. Halve, pit, and peel avocado, then dice. Mince chili, removing ribs and seeds first if you prefer less heat.
In a small bowl, combine remaining cilantro, ½ tsp cumin (we sent more), a pinch of minced garlic, and a pinch of chili (to taste). Stir in a squeeze of lemon and a large drizzle of olive oil. Season with salt, pepper, and more garlic and chili as desired. TIP: Add more lemon and olive oil as needed to give mixture a loose, drizzling consistency.
Cut half the grilling cheese into ⅓-inch-thick slices (save the rest for another use). When sweet potatoes and onion are almost done, heat a drizzle of olive oil in a large pan over medium-high heat (use a nonstick pan if you have one). Add grilling cheese and cook until browned, 1-2 minutes per side.
Add tomatoes, sweet potatoes, onion, avocado, a squeeze of lemon juice, and a pinch of remaining chili (to taste) to bowl with reserved cilantro. Toss to combine. Divide between plates, then top with grilling cheese. Drizzle with chimichurri and serve.