This southern 4-ingredient baked sweet onion dip is the kind of recipe that gets requested on repeat. I first made it for a casual backyard cookout, and my dad literally asked me to make a double batch the next time because the bowl was licked clean. It’s inspired by those old-school church potluck onion dips, but pared down to just four ingredients you probably already have. Everything bakes together in a cast iron skillet until the top is golden brown and bubbly, with a caramelized crust and a creamy, cheesy center. It’s low-effort, big payoff, and perfect for busy weeknights or last-minute entertaining.
Serve this dip straight from the cast iron skillet with sturdy dippers that can handle the warm, melty cheese—think thick-cut potato chips, toasted baguette slices, crackers, or pita chips. It also pairs really well with fresh crunchy veggies like celery sticks, bell pepper strips, and cucumber rounds to balance the richness. For a cookout spread, I like to set it next to grilled burgers, brats, and a big bowl of coleslaw so people can snack while the main food finishes on the grill. If there are leftovers, spoon some onto a baked potato or use it as a decadent spread for grilled chicken sandwiches the next day.
Southern 4-Ingredient Baked Sweet Onion DipServings: 8
Ingredients
2 cups finely chopped sweet onion (about 2 medium Vidalia or other sweet onions)
2 cups shredded sharp cheddar cheese, packed
1 cup mayonnaise
1/2 teaspoon kosher salt (or to taste)
Directions
Preheat your oven to 375°F (190°C). Place a 9-inch cast iron skillet on the counter so it’s ready to go. Lightly grease it with a tiny bit of mayo or a neutral oil if your skillet isn’t well-seasoned.
Finely chop the sweet onions. Aim for small, even pieces so they soften and almost melt into the dip as it bakes. Measure out 2 cups once chopped.
In a medium mixing bowl, combine the chopped sweet onion, shredded sharp cheddar cheese, mayonnaise, and kosher salt. Stir until everything is evenly mixed and no dry cheese shreds remain. The mixture will be thick and chunky.
Spoon the onion mixture into the cast iron skillet and spread it into an even layer, smoothing the top with a spatula. Try to get it all the way to the edges so it browns evenly.
Bake the dip on the center rack for 25–30 minutes, or until the top is deeply golden brown, bubbling around the edges, and the cheese has formed a caramelized crust. If your oven runs cool and it’s not browning, leave it in for an extra 5 minutes, keeping an eye on it.
Carefully remove the skillet from the oven and place it on a heat-safe surface. Let the dip rest for about 5–10 minutes before serving so it can thicken slightly and won’t burn anyone’s mouth. Serve warm, right from the skillet, with your favorite chips, bread, or veggies for dipping.
Variations & Tips
You can tweak this simple base to fit your crowd without losing the 4-ingredient spirit. For extra depth, swap half of the sharp cheddar for Monterey Jack or pepper jack for a little kick. If you like a stronger onion flavor, use 1 1/2 cups sweet onion and 1/2 cup finely chopped yellow onion. Prefer a slightly lighter version? Replace up to half of the mayonnaise with full-fat Greek yogurt or softened cream cheese (just know it may not brown quite as deeply on top). For a make-ahead option, mix everything together, spread it in the skillet, cover tightly, and refrigerate up to 24 hours; bake straight from the fridge, adding 5–10 minutes to the bake time as needed. Food safety tips: Always refrigerate any leftover dip within 2 hours of baking, and store it in an airtight container for up to 3–4 days. Reheat leftovers in a small oven-safe dish at 350°F until hot and bubbling; avoid leaving the dip out at room temperature for long periods, especially at outdoor cookouts in warm weather. Use pasteurized mayonnaise and keep raw ingredients refrigerated until you’re ready to mix and bake.
