Bone Broth French Onion Soup

The best bone broth French onion soup recipe you’ll ever make. This low-calorie, low-fat soup has all the flavor of and twice the amount texture and protein classic French onion soup. This soup also delivers a gut-healing boost of collagen and amino acids.

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French onion soup has to be one of my all-time favorite soups. It’s rich, full of flavor and has the perfect balance of different textures.

As a personal trainer, I’m always looking for ways to nutritionally elevate my favorite recipes. I love experimenting in the kitchen to find ways to make my favorite comfort foods healthy so that I can enjoy all the flavor while knowing I’m also fueling my body with wholesome nutrients.

Some classic French onion soup recipes can be surprisingly high in fat and calories while providing little in the way of protein. I wanted to create a lighter version that had less fat, more protein and could serve as a more nutritionally balanced meal.

This easy French onion soup recipe is low-calorie and low-fat compared to other recipes and takes things to the next level with the addition of two very special ingredients: Kale and bone broth.

What Makes This French Onion Soup Healthy

There are a lot of great things going on in this soup.

This bone broth French onion soup recipe is everything you know and love about traditional French onion with an extra boost of nutrients. And it’s all done through the help of a few nutrient-dense wholefood ingredients. Specifically fresh onions, kale and bone broth.

Nutritional benefits of onions:

• High in vitamins C, B and potassium
• Loaded with antioxidants
• May help control high blood pressure
• Support strong bones
• Contain antibacterial properties
• Rich in prebiotics

Nutritional benefits of kale:

• High in vitamins A, K and C
• Positive source of calcium, potassium and magnesium
• Loaded with antioxidants
• Can help lower cholesterol

Nutritional benefits of bone broth:

• High in protein (particularly collagen)
• Positive source of  calcium, magnesium, potassium and phosphorus
• Supports gut health
• Can help fight inflammation
• Supports joint health

It’s also provides double the amount of protein and half the amount of fat as other French onion soup recipes. A heaping bowl of this soup can serve as a wholesome meal. It’s so good (and low-calories) you won’t feel bad helping yourself to a second bowl!

A NOTE ON SALT:

This bone broth French onion soup utilizes Celtic sea salt. Here’s why that’s important.

Our family made the switch to less processed salts after doing some research to learn that not all salt is made (or processed) equally. Many brands of refined salt are depleted of much of their mineral and nutritional value.

Furthermore, we learned that 90 percent of common table salts (including sea, lake and rock salts)  may contain microplastics (i.e. little bits of plastic). 

We’ve made the switch to salt brands known for higher purity with less processing to retain more of their nutritional value. They’re fantastic for all kinds of cooking!

Celtic Sea Salt

(Non-GMO Verified, Vegan, Kosher and Paleo-Friendly)

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Recipe for Bone Broth French Onion Soup

INGREDIENTS:

The Soup:

• 1 Cup kale, stripped from stems and thinly sliced
• 4 Yellow onions, peeled and thinly sliced
• 4 Cups low-sodium bone broth
• 1 Chicken bouillon cube
• 2 Tablespoons low-sodium soy sauce
• 3 Garlic cloves, diced
• 2 Large sprigs fresh rosemary, finely chopped
• 2 Large sprigs fresh thyme, finely chopped
• 1 Bay leaf
• 2 Teaspoons coconut sugar
• 2 Tablespoons clarified butter
• Celtic salt (the only kind I use anymore)
• Black pepper

The Baguette:

• 1 Cup low-fat mozzarella cheese, grated
• 1 Garlic clove, halved
• 1 Small baguette

DIRECTIONS:

The Soup:

Pre-heat the oven to 500°F on broil.

Heat the butter in a large pot over medium heat. Add onions and saute for 10 minutes or until onions begin to soften. Sprinkle in the sugar, stirring occasionally for 20 minutes or so, until onions have browned and fully caramelized.

Add the 3 diced cloves of garlic, thyme and rosemary into the pot and stir together for about 1 minute, until herbs are fragrant. Pour vegetable stock, soy sauce and bay leaf into the pot and bring everything to a boil.

Reduce heat and allow to simmer 5-10 minutes. Stir in kale to wilt it. Give a taste and add salt and pepper to season as needed, then remove the bay leaf when done.

The Baguette

Thinly cut the baguette into 8 slices. Place them on a baking sheet, and place in the oven to toast for 1-2 minutes until a light golden brown (don’t take your eyes off them or they will burn at such a high temperature).

Remove them from oven and rub the halved garlic clove across the top of the slices to coat in a layer of garlic. Top them with the mozzarella cheese and pop them back into the oven for another 1-2 minutes until the cheese is gently toasted.

Serve soup hot and topped with 2 cheesy baguette croutons! Makes 4 servings.

(Substitutions and macros listed below.)

Ingredient Substitutions

• If you don’t use animal products or byproducts (like bone broth or animal based bullion cubes), vegetable stock and vegetable bullion cubes are the perfect flavorful substitute (just know that without the bone broth, your overall protein macronutrient content will go down in the overall recipe).
• If you don’t have access to fresh herbs you can use dried herbs with 1 Tablespoon rosemary and 1 Tablespoon thyme.
• Brown sugar can be swapped in for the coconut sugar.
• Don’t consume dairy? Try coconut oil or olive oil in place of the clarified butter.
• Vegan cheese will do the trick in place of dairy cheese.
• Can’t get your hands on a baguette? A regular slice of whole wheat bread will do for each bowl of soup!
• Going gluten-free? Swap out the baguette for a gluten-free roll or nix the bread altogether.
• When making substitutions, just keep in mind that your macro count may slightly vary from this specific recipe. If you’re counting macros, just make sure to adjust the recipe macros in a macro calculator based on the ingredients you use.

Macronutrient & Nutrition Info

MACROS PER SERVING (soup without baguette): 

• Calories: 290
• Carbs: 22g
• Fat: 13g
• Protein: 23g

MACROS PER SERVING (soup with baguette): 

• Calories: 358
• Carbs: 35g
• Fat: 13g
• Protein: 26g

Video Tutorial: Bone Broth French Onion Soup in Sign Language

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Related Soup Recipe Articles

• Spicy Southwest Pumpkin Soup
• Savory Squash Soup

Related Onion Recipes

• Southern Savory Roasted Onion Side Dish
• Vegan French Onion Wrap

More Recipes with American Sign Language Video Tutorials:

• How to Make Almond Milk
• Pina Colada Smoothie
• Apple Pie Protein Smoothie
• Orange Creamsicle Smoothie
• How to Make Easy Sushi 
• How to Make Perfect Baked Asparagus
• How to Make Oat Milk from Scratch

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All writing and images copyright © 2020 Rachel Elise Weems Woods

Originally published 6-16-18. Updated 10-05-2020.