Caramelized onions are made to sound way harder to make than they actually are. Sure, they take a bit of time to cook down and become jammy, but other than the occasional stirring, there’s really not much effort that goes into it.
A few key things to remember and you’re good to go – start by getting out your largest, widest pan. The more the surface area, the quicker they will brown. Spread them out evenly in the pan and let cook, stirring occasionally. As soon as the onions start sticking to the pan, let them stay and brown, but stir before they burn. The trick is to leave them undisturbed long enough to brown (if you stir them too often, they’ll take a LOT longer). Go by eye. They are done when that massive heap you started out with has wilted down to almost a third.
Sour dough works best here but any bread you have to hand will do. Once you heap on the fillings, make sure to press down the sandwich with something heavy – a mortar/saucepan/a foil covered brick if you’re Nigella, anything goes. This gets you maximum browning on the underside and also ensures that very desirable cheese pull.
CARAMELIZED ONION, TOMATO & MOZZARELLA SANDWICH
- 4 large onions, thinly sliced
- 150 grams mozzarella cheese, thinly sliced
- 2 large tomatoes, thinly sliced
- 2 tablespoons olive oil
- 8 slices of your bread of choice (sourdough works best)
- 1 teaspoon black pepper
- 1 teaspoon salt
- Heat the olive oil in a large wide pan. Add the onions, salt and pepper and cook over medium heat. Spread them out evenly in the pan and let cook, stirring occasionally.
- As soon as the onions start sticking to the pan, let them stay and brown, but stir them before they burn. The trick is to leave them undisturbed to brown (if you stir them too often, they'll take a lot longer to brown).
- Cover and cook for a few mins if they appear too dry and start sticking to the pan. It will take anywhere between 20-30 mins for them to caramelize and soften.
- To assemble: butter all the bread on one side. Place half of them on the pan with the buttered side down.
- Add a good amount of caramelized onions on top and spread them out evenly. Top with a layer of tomatoes and then mozzarella slices. Add the other slice of bread on top (buttered side up).
- Press down the sandwich firmly with a saucepan/mortar. Flip when the bottom side is golden brown. Do the same with the other side. Serve immediately.