I grew up in a restaurant. No, literally. I did. My parents owned a restaurant and they were there all the time, so in turn I was there all the time. It had its upsides and its downsides.
A downside? My parents worked more than any other parents I knew.
An upside? A work ethic was naturally instilled in me at a young age.
A downside? We didn’t get to have dinner as a family most nights.
An upside? I could order pretty much whatever I wanted for dinner.
While I could have ordered steak or freshly caught local whitefish every night, I was mostly content eating grilled peanut butter and jelly sandwiches. No, those weren’t on the menu. I did order them a lot, though. Those and grilled cheese sandwiches.
Grilled cheese was on the menu, but it wasn’t plain grilled cheese. It was grilled cheese with onions and tomatoes. And I loved it. 
The epic grilled cheese sandwich at my parent’s restaurant may have ruined regular grilled cheeses for me forever. Just cheese? Blah-so boring. Add some flavorful onions and fat tomatoes and I’m in heaven.
The onions on the grilled cheese of my youth were grilled, but not caramelized. I took it a step further because caramelized onions are like gold. I could eat a plate of them alone. Yes, they take some extra time. Most of the time I’m not up for that. But sometimes, my friends, it’s worth it. 
The Ultimate Grilled Cheese Sandwich with Caramelized Onions and Tomato
If you try this grilled cheese with caramelized onion and tomato, you may never want to go back to a regular grilled cheese again. You’ve been warned!
- Prep Time: 5 minutes
- Cook Time: 40 minutes
- Total Time: 45 minutes
- Yield: 2 servings 1x
- Category: Sandwich
- Cuisine: American
Ingredients
4 large onions, thinly sliced
1–2 tablespoons oil extra virgin olive oil
1 large tomato, sliced
sharp cheddar cheese (I like it thick cut for this)
butter
4 slices whole grain bread
Instructions
Put your onions in a medium/large skillet pan over medium heat. Cover and cook, only stirring occasionally, about 15 minutes. Add the oil and a pinch of salt and reduce the heat to medium low. Continue to cook, stirring occasionally, until the onions are caramelized to your liking. It can take 5 minutes or another 45 minutes, depending on how deeply caramelized you like them.
(Tip: if you like caramelized onions a lot, double or triple this batch so you have some extra to keep in the refrigerator. They taste great on everything!)
When your onions are ready, you are ready to make your sandwich. Start by buttering the outside of your bread pieces and adding a little butter to a skillet over medium heat. Add enough cheese to cover your bread slice, then add enough tomato slices to also cover the area of the bread. Top with half of the caramelized onions and the final piece of bread.
Place the sandwiches in the skillet and cook for about 2-3 minutes on one side. Carefully flip the sandwich and cook another 2-3 minutes. If your cheese is not melted (sometimes I slice my cheese a little too thick…) add about a tablespoon of water to the skillet, not too close to the sandwich so it gets your bread wet, and cover the skillet. The cheese should melt quickly. Enjoy!
Nutrition
- Serving Size: 1 serving
- Calories: 515
- Sugar: 15.5g
- Sodium: 110mg
- Fat: 21g
- Carbohydrates: 75g
- Protein: 16.5g
Hi!!!
When you prep this sandwich do you put the “filling” on the buttered or non-buttered side of the bread?
Another way to say this would be dies the bread go into the skillet butter-side-down (which I’m assuming is right) or. butter-side-up?
Thank you.
Butter side down is correct! You put the filling on the non-buttered side of the bread and the buttered side goes into the skillet.