Buttery, gooey and warm, grilled cheese is a timeless comfort food, but this signature sandwich goes beyond white bread and slices of American cheese. While the tomato soup-paired classic is indeed a favorite among kids — and, of course, adults at times — it's easy to dress up this between-bread creation and turn it into a grown-up meal by making a few simple ingredient swaps. Think of flavor combinations you know work well and use those to inspire your filling picks. Re-create the taste of French onion soup by layering sweet, soft caramelized onions with nutty Gruyere cheese. Craving a bite that's both sweet and savory? Try combining indulgent Camembert with crisp apple slices and caramel sauce.

Food Network Kitchens embraces smoky flavors in its recipe for Roasted Poblano and Mushroom Grilled Cheese (pictured above), an easy-to-make dish that can serve as a simple dinner or a go-to lunch. After sauteing earthy, meaty portobellos, layer them atop thick-cut Cuban sandwich bread with creamy Monterey Jack cheese and sliced peppers, then finish the sandwich with a second slice of bread, this time brushed with tangy chipotle in adobo puree (it's the crimson-colored puree inside a can of chipotle peppers in adobo). The secret to this recipe is roasting the poblanos — all it takes is a few minutes under the broiler or over an open flame to char the skin on these mild peppers and replace their usual bite with a tender consistency. Be sure to brush the outer sides of both slices of bread with butter to guarantee a deliciously golden-brown, crunchy exterior.

Get the Recipe: Roasted Poblano and Mushroom Grilled Cheese

Meatless Monday, an international movement, encourages people everywhere to cut meat one day a week for personal and planetary health. Browse more Meatless Monday recipes.