This rich, deeply flavorful French onion soup is made entirely from scratch, starting with fire-roasted onions and a homemade beef bone marrow broth. Topped with garlic-parsley croutons and Gruyère cheese, it’s the ultimate comfort food straight from the grill.
Ingredients
For the beef broth
2.5 kg / 5.5 lbs bone marrow bones
1 kg / 2.2 lbs yellow onions
1 whole bunch of celery
1 kg / 2.2 lbs carrots
Water to cover
- 1 tbsp PitmasterX Texas seasoning
For the roasted onions
2.5 kg / 5.5 lbs large yellow onions
For the sautéed onions
Roasted onions, peeled and sliced
50 g / 3.5 tbsp butter
For the croutons
½ baguette or rustic bread, cut into cubes
2 tbsp olive oil
1 tbsp minced garlic
1 tbsp chopped fresh parsley
- 1 tsp PitmasterX Texas seasoning
Pinch of salt
Grated Gruyère cheese
Tools
Thanks to Napoleon Grills for sponsoring this recipe Visit their website to learn more.
How to
- While the grill is heating, prepare the bone marrow by placing the bones on a wire rack and seasoning them with PitmasterX Texas seasoning.
- Place the whole unpeeled onions directly into the hot charcoal and rotate them every couple of minutes until fully roasted.
- At the same time, lower the charcoal base, replace the grill grates, and place the seasoned bone marrow on top to pick up smoke while slowly roasting.
- Meanwhile, quarter 1 kg of onions, roughly chop celery and carrots, and place all the vegetables in a large pot.
- Once the onions are deeply charred and sizzling in their skins, remove them from the grill and let them cool.
- Remove the bone marrow from the grill once it has a light roast but is still soft inside. Add it to the vegetable pot.
- Fill the pot with water to cover the ingredients, place it over the fire, and simmer for at least 4 hours to make a rich beef broth.
- While the broth is simmering, peel the roasted onions, remove any overly charred skin, and slice them thinly.
- Heat a cast iron skillet over low heat, add butter, and sauté the sliced roasted onions slowly until caramelized and soft, without browning too much.
- Transfer the sautéed onions to a clean pot.
- Strain the finished beef broth and add it gradually to the onions, stirring to combine and checking consistency—it should remain a soup, not a porridge.
- Adjust seasoning with salt to taste, and reduce further if you want a thicker soup.
- For the croutons, mix bread cubes with olive oil, minced garlic, chopped parsley, PitmasterX Texas seasoning, and a pinch of salt.
- Roast the croutons over an open fire until golden and crispy.
- To serve, ladle the hot onion soup into a bowl, add a small pile of croutons in the center, and grate Gruyère cheese over the top.
- Finish under a broiler or hot grill until the cheese is just melted. Serve piping hot and enjoy what might just be the world’s best onion soup.
