Grilled cheese is one of those foods that never asks for much—just bread, butter, and melty cheese. But once I started playing around with add-ins, it became something else entirely.
Some combos turned it into a grown-up sandwich; others made it feel like a flavor-packed surprise tucked inside childhood nostalgia. Whether you’re using sourdough or plain white, these ingredients take it to a whole new level.
1. Caramelized Onions
Slow-cooked until deep golden and sweet, caramelized onions bring out a rich, jammy depth that pairs beautifully with sharp or melty cheese. I usually make a big batch and stash them in the fridge—they keep for days and go with everything.
Their sweetness softens the saltiness of the cheese. Bonus: your kitchen will smell amazing.
2. Sliced Avocado
Creamy, cool, and mild in flavor, avocado adds a buttery layer that melts into the cheese like a dream. I like to fan thin slices over the bread right before grilling so they stay intact.
A pinch of salt and a squeeze of lemon bring out its best side. Pair with pepper jack or cheddar for contrast.
3. Crispy Bacon
Nothing wakes up a grilled cheese like a few strips of crisp, salty bacon. It adds crunch and a hit of umami that turns the sandwich into a full-on meal.
I always pat the bacon dry so it doesn’t sog up the bread. Smoky gouda or cheddar make perfect partners.
4. Fresh Tomato Slices
Juicy slices of tomato add brightness and acidity that cut through rich cheese like a knife through… well, cheese. I blot them with a paper towel before using so they don’t make the bread soggy.
A touch of salt makes them pop. Mozzarella or provolone brings everything together.
5. Roasted Red Peppers
Sweet, smoky, and soft, roasted red peppers add color and a little fire-roasted depth. I love them with goat cheese or havarti for contrast.
Slice them thin so they melt into the sandwich rather than slipping out. Jarred ones work great in a pinch.
6. Pickled Jalapeños
Zippy and just hot enough to wake up your palate, pickled jalapeños bring heat and tang in one go. They’re especially good with milder cheeses like Monterey Jack or mozzarella.
I chop them up to avoid uneven bites of fire. A drizzle of honey takes it to the next level.
7. Pesto Sauce
Spread a thin layer of pesto on the inside of the bread before adding cheese—it melts in and infuses everything with garlicky, herby magic.
I like basil pesto best, but sun-dried tomato or arugula versions are fun too. Works beautifully with fresh mozzarella or Swiss.
8. Fig Jam
Sweet and sticky, fig jam turns grilled cheese into a café-style sandwich. It plays best with creamy cheeses like brie or fontina.
I spread it thin so it doesn’t overpower everything else. A sprinkle of black pepper gives it a savory edge.
9. Sautéed Mushrooms
Earthy and rich, mushrooms bring an almost meaty quality to grilled cheese. I sauté them in butter with garlic until golden and tender. Swiss or provolone really lets them shine.
Just don’t skip the salt—it brings out their flavor like magic.
10. Fried Egg
Slide a just-set fried egg onto your cheese before grilling and you get a golden, runny surprise with every bite. It makes the sandwich extra decadent and satisfying.
I usually grill the sandwich first, then tuck the egg inside before slicing. Perfect for breakfast—or late-night snacks.
11. Apple Or Pear Slices
Thinly sliced apples or pears give you that crunchy-sweet bite that balances salty cheese in the best way. I love sharp cheddar with apples or brie with pears.
Slice them paper-thin so they soften slightly while grilling. Cinnamon or honey adds an extra twist if you’re feeling bold.
12. Spicy Mustard
A thin swipe of spicy mustard cuts through melty cheese with a vinegary punch that keeps things interesting. Dijon, whole grain, or even horseradish mustard all do the job.
Use it on one slice of bread so it doesn’t overwhelm the cheese. I love it with ham or smoked cheese blends.
13. Kimchi
Fermented, funky, and full of personality, kimchi turns your grilled cheese into something unforgettable. I chop it up a bit before adding so it layers easily.
Cheddar, mozzarella, or even American cheese all work as mellow bases. Expect a little tang, a little heat, and a lot of crunch.
14. Fresh Basil Or Arugula
Greens like basil or arugula add a peppery, herbal freshness that breaks through all that richness. I toss them in just before grilling so they stay bright.
They’re especially nice with mozzarella or mild Swiss. Add a slice of tomato and you’ve got a mini caprese.
15. Extra Cheese Blends
Sometimes the upgrade is just… more cheese, or better cheese. Mixing something melty with something sharp or creamy gives the sandwich dimension.
Fontina melts beautifully, gouda adds depth, and brie brings that soft, luxurious texture. I often layer two types together just because I can.