Caramelized Onion Burger with Sweet Peppers

This juicy caramelized onion burger features caramelized onions and sweet peppers packed both inside the burger for extra flavor and more piled on top with a slice of pepperjack cheese and crisp lettuce.

I’m getting all my ducks in a row for 4th of July in a few weeks and this burger is front and center in those plans. In all its caramelized onion + pep glory.

You’ve gotta go big or go home in the burger department if you’re grilling for the 4th of July and this one ticks ALL the boxes. We’ve got caramelized onions and peppers hanging out not only in the meat but ON it as well alongside melty pepperjack, crisp lettuce, and tomato slices.

It may look simple but trust, the flavors absolutely deliver here. And yes, I’m solely blaming those glorious onions + peppers.

They’re saucy, sweet, and literally everything you could ever want on a burger. I’m almost embarrassed to admit how fast my husband and I can throw down one of these bad boys.

These Burgers Feature…

• Flavorful caramelized onions and sweet peppers
• Juicy beef patties stuffed with caramelized mixture
• Pepperjack cheese, crisp lettuce, and tomatoes

Making the Burgers

(scroll down to the bottom of the post for the full recipe)

Ingredients You Will Need

• Unsalted butter
• Sweet onion
• Garlic
• Balsamic vinegar
• Sweet pepper
• Ground chuck
• Spices
• Pepperjack cheese
• Buns
• Lettuce
• Tomato

Choosing Your Beef

I recommend using an 80/20 ground chuck for these burgers. This ratio means 80% lean meat and 20% fat which I find leads to an incredibly juicy and tender burger.

You can use regular ground beef if that’s all you have on hand, but be aware your burger will likely not turn out quite as juicy.

Temperature Cooking Guide

Use this temperature chart to determine when to pull your burgers off the heat for your desired level of doneness. Always use a kitchen thermometer to test the internal temperature.

• Rare – 120-125F
• Medium-rare – 130-135F
• Medium – 140-145F
• Medium-well – 150-155F
• Well-done – 160-165F.

Tips for Perfect Burgers

1. Use a heavy-bottom pan for onions – I prefer to use cast iron for even heat distribution.
2. Caramelize onions over medium-low heat – it takes time and patience to caramelize onions so don’t be tempted to bump up the heat during cooking.
3. Cook sweet peppers separately – the sweet peppers will only take a few minutes to turn tender so I like to cook these separate from the onions and combine them afterwards.
4. Mince half of onion/pepper mixture – this will get added to the meat itself for extra flavor throughout the burgers. Save the other half of mixture for topping burgers later.
5. Don’t overknead meat – handle the beef with care to avoid overmixing and turning it tough.
6. Prep all burger toppings before grilling – ideally, you will want all the toppings prepped before you start cooking the burgers. This way once the burgers are off the grill you can assemble and serve them immediately while warm.
7. Preheat grill to 400F – you always want your grill preheated prior to adding the meat.
8. Toast buns – this only takes a moment and instantly elevates any burger. I usually toast my buns directly on the grill after grilling burgers.
9. Season tomato slices – a little salt brings extra flavor out of the tomatoes.

Recipe Variations

Try these ideas for a different twist on these burgers.

• Add a sauce – barbecue sauce, ketchup, or ranch would all be great additions here.
• Caramelize onions + peppers ahead of time – you can store these in the refrigerator up to 4 days. Reheat onions and peppers on grill before using.
• Make burgers into a salad – skip the buns and instead cut the burgers into bite-sized pieces and arrange over a bed of lettuce with toppings and dressing.

Burger Topping Ideas

You can use my suggested toppings of pepperjack cheese, lettuce, and tomato or try the additional options below!

• Crispy bacon strips
• Another kind of cheese (cheddar, swiss, provolone, or mozzarella)
• Pickles
• Avocado
• Jalapeno peppers

Friends, this is THE burger to pull out if you’re looking to seriously wow in the grilling department this year! No one can resist those onions and sweet peppers in all their caramelized glory. They kick all the flavors up a notch and pair seriously like a dream with the juicy burger base.

Just be prepared to crave this nonstop all summer.

Save this recipe using the ‘save to recipe box’ button below. If you make it, please let us know! Leave a comment + star rating below, or take a photo and tag it on Instagram with #wholeandheavenlyoven.

More summery burgers to make next!

• Cowboy Burgers
• Blackberry Blue Cheese Burgers
• Whipped Feta Turkey Burgers