Why You Should Caramelize Your Onions in Bacon Fat | America’s Test Kitchen (2024)

People have strong preferences when it comes to burger toppings. (Fried eggs are a particularly controversial one.) But in my opinion, there are two essential toppings: caramelized onions and bacon.

Bacon adds a wonderful salty crunch to a burger, and caramelized onions bring a sweet element that balances all of that saltiness perfectly.

So why not combine the two?

Our recipe for Grilled Bacon Burgers with Caramelized Onion does just that. Bacon isn’t a topping but instead a component in the patty mixture, providing bacon flavor in every bite. But once that bacon is cooked, we don’t throw away the fat. We use it to take the burger to the next level.

This is where the caramelized onion comes in.

After cooking the bacon in a skillet, we reserve the bacon fat and then use it to caramelize the onion. Twenty minutes of cooking results in a sweet, almost spreadable, bacon-y onion mixture.

But you don’t have to make this particular burger recipe to have next-level caramelized onions on hand. Made a bunch of bacon for breakfast? Take that onion you have sitting on your counter and take advantage. Save the bacon-caramelized onion for later, or even put it in an omelet or on your breakfast sandwich.

Or do you happen to have some leftover bacon grease sitting around that you don’t know what to do with? Today’s your lucky day. Use the bacon-caramelized onions for a burger, an onion dip, or a spread on crackers.