Soup Series: French Onion Soup (Crockpot Style with Homemade Broth)

There’s something deeply satisfying about finally checking a recipe off your “someday” list especially when it turns out to be this good. I’ve always wanted to try making French Onion Soup from scratch. There’s a kind of magic to it: the slow transformation of humble onions into golden sweetness, the rich aroma of broth simmering all day, and that final, irresistible layer of melted cheese bubbling over crisp bread.

And now that I’ve made it, I can honestly say it’s become an instant favorite in our kitchen.

This one’s a keeper, friends. And as part of our Soup Series, it perfectly captures what I love about soup season: simple ingredients, slow comfort, and flavors that bring people together.

🌿 Day 1: Homemade Beef Broth (Optional but Amazing)

If you’ve ever wondered what gives restaurant French Onion Soup that deep, velvety flavor this is it. While store-bought broth works just fine, taking the time to make your own adds layers of richness that can’t be replicated.

Ingredients:

• 2–3 lbs beef bones (marrow bones or oxtail work best) *we used marrow bones*

• 1 onion, quartered (leave skin on for color)

• 2 carrots, cut into chunks

• 2 celery stalks, cut into chunks

• 4 garlic cloves, smashed

• 2 bay leaves

• 1 tsp peppercorns

• Fresh thyme sprigs (or 1 tsp dried)

• 12 cups water
  

  

  
  
  
  

Instructions:

1. Roast the bones (optional but worth it): Spread bones on a baking sheet and roast at 400°F for 25–30 minutes until golden.
   

2. Simmer the stock: Add bones, veggies, herbs, and water to a large pot. Bring to a boil, then reduce to a gentle simmer for 6–8 hours.
   

3. Strain and chill: Discard solids, cool, and refrigerate overnight. Skim fat before using.

The result? A deep, flavorful base that elevates everything it touches.

🧅 Day 2: The Main Event — French Onion Soup

Ingredients:

• 4–5 large yellow onions, thinly sliced

• 3 Tbsp butter

• 2 Tbsp olive oil

• 1 tsp salt

• 1 tsp sugar (to help caramelize)

• 6 cups beef broth (homemade or store-bought)

• ½ cup dry white wine (optional, but adds beautiful depth)

• 2 tsp fresh thyme (or 1 tsp dried)

• 2 bay leaves

• Salt & pepper to taste
  

For the topping:

• 1 baguette, sliced and toasted

• 2 cups Gruyère cheese (or Swiss/Mozzarella)
  

🕯️ How to Make It

1. Caramelize the onions. In a large skillet, heat butter and olive oil over medium heat. Add onions, salt, and sugar. Stir often and cook slowly—about 30–40 minutes—until they turn deep golden brown.(This step gives the soup its soul—don’t rush it!)

2. Load the crockpot. Transfer the caramelized onions to your crockpot. Add broth, wine, thyme, bay leaves, and seasoning. Stir well.

3. Cook. Cover and cook on Low for 6–8 hours (or High for 3–4) to let all those cozy flavors mingle.

4. Prepare the bread. Slice your baguette and toast it under the broiler until golden and crisp.

5. Assemble and broil. Ladle soup into oven-safe bowls. Place toasted bread on top, sprinkle generously with cheese, and broil until the cheese is melted, bubbly, and golden.

6. Serve & enjoy. Carefully remove the bowls (they’ll be hot!) and dive in. Every spoonful is a little celebration of patience and simplicity.

🌾 Tips & Variations

• Add a splash of balsamic vinegar or Worcestershire sauce before serving for extra depth.

• If you don’t have oven-safe bowls, melt the cheese-topped bread separately on a sheet pan, then float it on top of each serving.

• The soup base freezes beautifully just leave off the bread and cheese until ready to reheat.
  

🕰️ Final Thoughts

What I love most about this recipe is how something that seems fancy can be so simple. It’s built from nothing more than time, love, and a handful of ingredients that transform into something extraordinary.

Whether you go all-in with the homemade broth or take the simpler route, this French Onion Soup is a reminder that slow, intentional cooking can be both easy and amazing.

This bowl is pure comfort deeply flavorful, gently sweet, and topped with that golden, cheesy crown. And now that I’ve made it once, it’s earned a permanent place in our Soup Series favorites. We meant to capture the finished bowl, but it was gone before we remembered proof that patience, flavor, and a little love make something truly irresistible. ✨

The heart of every great soup begins here — slow, steady, and full of intention.