French Onion Sloppy Joes

5 from 28 votes

These French Onion Sloppy Joes feature savory ground beef, melted Swiss cheese, and thyme-infused caramelized onions piled onto soft sandwich buns. They’re an easy, budget-friendly dinner or game day meal.

Prep Time5

Cook Time30

Total Time35

Course: dinner, main course ground beef, Sandwich

Cuisine: American Comfort Food

Keyword: French Onion Sloppy Joes, game day sandwiches, Homemade Sloppy Joes, Sloppy Joes with caramelized onions, Thyme-Infused Caramelized Onions

Servings: sandwiches

Calories: 323kcal

Author: Renee Goerger

Equipment

large cast iron skillet optional
large high-sided skillet
cutting board
chef's knife
butcher's twine optional
cheesecloth optional
measuring cups and spoons
slotted spatula
serving spoon
airtight container optional if making the onions in advance.
food storage labels optional

Ingredients

For the thyme-infused caramelized onions:

4 sweet onions thinly sliced
3 tablespoons butter
10 sprigs fresh thyme
½ teaspoon salt
¼ teaspoon pepper

For the homemade sloppy joes:

2 pounds ground beef
1 cup celery , diced
6 ounces tomato paste
¼ cup brown sugar , packed
3 tablespoons apple cider vinegar
2 teaspoons salt
1 teaspoon pepper
10 slices Swiss Cheese
10 each hamburger buns
2 tablespoons grapeseed oil avocado oil also works

Get Recipe Ingredients

Instructions

To make the thyme-infused caramelized onions:

Melt the butter and oil in a large skillet over medium heat.
Add the onion slices. Stir well to coat the onion in the oil and butter.
Make a thyme bundle by wrapping the thyme sprigs with butcher's twine or wrap them in cheesecloth.
Add the thyme bundle to the onions.
Cook, over medium heat, stirring occasionally until the onions are deeply caramelized and reduced in volume (approximately 25-30 minutes).
Remove the thyme from the skillet and discard and season the caramelized onions with salt and pepper. Stir.
Keep the onions warm until serving, or store the onions in an airtight container in the refrigerate for up to 4 days if making them in advance.

To make the homemade sloppy joes:

In a large skillet, brown the ground beef and chopped celery.
Stir in the tomato paste and cook for an additional 2-3 minutes, stirring occasionally.
Stir in the brown sugar and apple cider vinegar.
Season with salt and pepper.
Cook, stirring occasionally, for an additional 3-4 minutes until the flavors have married and the sloppy joes are heated through.
Serve the sloppy joes on buns and top with slices of Swiss cheese (the cheese will melt) and a helping of thyme-infused caramelized onions.

Notes

The thyme-infused caramelized onions may be made in advance and refrigerated for up to 4 days in an airtight container. Reheat the onions before adding them to the sandwich for serving.

I like to serve these sandwiches open-faced because they're easier to eat, but that's your call.

The sloppy joe mixture may be frozen (without the buns) for up to 3 months stored in an airtight freezer container or freezer bag. Label and date. Thaw in the refrigerator overnight.

The thyme-infused onions can also be frozen in an airtight freezer container or bag. Label and date. Freeze for up to 2 months. Thaw in the refrigerator overnight.

Nutrition