Cheesy Skillet French Onion Pull-Apart Garlic Bread Step-by-step instructions

Before you start

Before starting, bring the butter to room temperature for easy spreading. Slice the onions and mince the garlic. Shred the cheeses if not pre-shredded—freshly shredded melts better.

Preheat the oven to 375°F (190°C) and have your cast iron skillet ready. The caramelization takes about 25 minutes, so plan accordingly.

Instructions

Caramelizing the Onions

1. 1Caramelize the Onions
   Heat a large skillet over medium heat and melt 2 tbsp butter. Add the sliced onions and fresh thyme. Cook slowly, stirring occasionally, for 25 minutes until the onions are deeply caramelized, dark mahogany brown, and sweet. If they begin to stick, add a splash of water. Remove from heat and let cool slightly.
   Look for Onions are soft, jammy, and deeply browned with a sweet aroma.
   Tip Low and slow is key: resist raising the heat to avoid burning.
2. 2Make Garlic Butter
   In a small bowl, combine the softened butter, minced garlic, salt, and pepper. Mash with a fork until well blended. Set aside at room temperature.
   Look for Butter is smooth and fragrant with garlic.
   Tip Use room-temperature butter for easy spreading.

The onions should be soft, dark mahogany brown, and jammy. They will have reduced significantly and smell sweet and savory. The garlic butter should be smooth and fragrant. This phase sets the flavor foundation for the entire dish.

Assembling the Bread

3. 3Score the Bread
   Place the sourdough boule on a cutting board. Using a serrated knife, cut a diamond cross-hatch grid into the bread, slicing about 1 inch apart and being careful not to cut through the bottom crust. The cuts should create a pattern of diamond-shaped wedges.
   Look for Bread is scored in a diamond pattern without cutting through the base.
   Tip Keep the bottom intact so the bread holds together.
4. 4Stuff the Bread
   Gently pry open each cut and spread the garlic butter inside every crevice. Stuff the caramelized onions evenly into the cuts, then push the shredded Gruyère and mozzarella into the openings, making sure the cheese reaches deep into the bread. Press the bread together gently to keep the filling in place.
   Look for Every cut is filled with butter, onions, and cheese.
   Tip Use your fingers or a small spoon to stuff the cheese into the cuts.

The bread is scored in a diamond pattern without cutting through the bottom. Every cut is filled with garlic butter, onions, and cheese.

The bread should look generously stuffed but still hold its shape. The cheese should be packed in tightly.

Baking and Broiling

5. 5Bake in Skillet
   Place the stuffed bread in a cast iron skillet. Loosely cover with aluminum foil and bake at 375°F (190°C) for 15 minutes, until the bread is heated through and the cheese begins to melt.
   Look for Bread is warm and cheese is starting to melt.
   Tip The foil prevents the top from over-browning before the inside melts.
6. 6Broil to Golden
   Remove the foil and switch the oven to broil. Broil for 3 minutes, watching closely, until the cheese is golden and bubbling and the bread edges are crunchy.
   Look for Cheese is bubbly and browned in spots; bread is crisp.
   Tip Watch carefully—broilers vary and can burn quickly.
7. 7Rest and Serve
   Remove the skillet from the oven and let the bread rest for 5 minutes. Serve warm, pulling apart the wedges to reveal the molten cheese and sweet onions.
   Look for Bread is slightly cooled but still warm and cheesy.
   Tip Resting helps the cheese set slightly for easier pulling.

After baking, the bread is warm and the cheese is melted. After broiling, the top is golden and bubbling, and the edges are crunchy. The cheese should stretch when you pull a piece. Let it rest briefly before serving.

Common mistakes

A common mistake is not caramelizing the onions long enough—they need to be deeply browned and sweet, which takes a full 25 minutes. Another is cutting through the bottom of the bread, which causes the filling to leak out.

Be gentle when stuffing to avoid tearing the bread. Also, don’t skip the foil during the first bake; it prevents the top from burning before the inside is warm.

How to tell it’s done

The bread is done when the cheese is fully melted and bubbling, with golden-brown spots from the broiler. The edges of the bread should be crunchy to the touch, and the center should be soft and hot.

If you insert a knife into the center, it should come out hot and cheesy. There is no raw protein in this recipe, so no internal temperature is required.