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French Onion Beef Sloppy Joes Recipe
Ash Tyrrell

French Onion Beef Sloppy Joes Recipe

I have to tell you, I wasn’t expecting to fall in love with a sloppy joe twist until I made this French Onion version. From the moment I started caramelizing the sweet onions with thyme, I knew this would be something special. The combination of savory beef, rich tomato paste, and melted Swiss cheese is downright irresistible
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Prep Time 15 minutes
Cook Time 25 minutes
Ingredients Method Notes

Ingredients
  

  • sweet onions sliced – choose fresh, sweet onions for a natural sweetness that caramelizes beautifully
  • fresh thyme sprigs – adds an earthy aromatic flavor to your onions
  • ground beef – I recommend 80/20 for juiciness and flavor
  • chopped celery – adds subtle crunch and balances richness
  • tomato paste – intensifies the beefy flavor; use the good-quality kind
  • brown sugar – enhances the caramelized onions and adds depth
  • apple cider vinegar – gives a subtle tang that cuts through richness
  • Swiss cheese slices – melt fresh slices over the sloppy joe for best flavor
  • grapeseed oil or other neutral oil – helps onions caramelize without overpowering them
  • butter – enriches the onions for that classic French onion flavor
  • salt and pepper – season to taste for balance
  • buns – I prefer soft lightly toasted buns to hold all the filling

Method
 

  1. I start by melting butter and oil in a large skillet. Then I add the sliced onions and toss them so they’re coated evenly. Adding a thyme bundle gives the onions a sweet, aromatic flavor as they cook down to golden perfection.
  2. Next, I brown the ground beef and diced celery over medium-high heat, seasoning with salt and pepper. Stirring occasionally ensures even cooking and prevents sticking. I like to cook until the beef loses its pink color completely.
  3. Once the beef is cooked, I stir in tomato paste and brown sugar, mixing thoroughly. Then I splash in apple cider vinegar, letting it simmer until everything is well combined. This step gives the sloppy joes a slightly tangy, rich flavor.
  4. I pile the beef mixture onto toasted buns and top each with a slice of Swiss cheese. Finally, I spoon generous mounds of the thyme-infused caramelized onions on top. The sandwich is ready to serve immediately while everything is warm and melty.

Notes

  • I always toast the buns lightly for texture
  • Adding celery provides a subtle crunch that balances the rich beef
  • I prefer fresh thyme over dried for more vibrant flavor
  • Don’t skip the apple cider vinegar—it brightens the dish beautifully
  • Caramelize onions slowly; rushing them will reduce depth of flavor