Roasted Garlic, Mushroom, and Onion Soup

What do you get when you cross french onion, cream of mushroom, and 40 clove garlic soup? This baby is packed with roasted garlic, toasty mushrooms, and caramelized shallot flavor, and the classic french onion cheesy topping takes it to the next level. 

Trust the process and don’t rush

This isn’t a “get dinner on the table in 30 minutes” kind of recipe. This soup gets the majority of its flavor from taking things slowly: roasting the garlic until sweet and tender, painstakingly caramelizing onions (no shortcuts here!), and taking the extra time to roast the mushrooms before adding them to the pot. However, this doesn’t mean that this roasted garlic and mushroom soup is particularly difficult or complicated. Plan to make this on a lazy Saturday afternoon, maybe one where you start drinking wine around 3 PM. Sure, it takes 3 hours, but most of that time is spent waiting for garlic to roast and onions to caramelize. If you think the process of cooking is relaxing, this is the perfect recipe for you. 

roasted garlic mushroom and onion soup

Take it Step by Step

First, you will roast garlic until brown and tender. 

Next, slowly caramelize onions and shallots. Don’t rush this process! It takes 40-60 minutes.

While the onions caramelize, roast the mushrooms. Spread the mushrooms out across two baking sheets to ensure they don’t steam.

roasted mushrooms

Next, make the roasted garlic broth by combining water, better than bouillon, the roasted garlic, and some soy or Worcester sauce. Use an immersion blender to emulsify. 

Add the mushrooms to the caramelized onions, along with some fresh herbs. Deglaze with wine and add a bit of flour to thicken. Add the broth and simmer for 10 minutes. Finish up with a touch of cream.

Ladle into oven safe bowls and top with toasted bread and lots of gruyere. 

Finally, broil until brown and bubbly.


Roasted garlic, Mushroom, and Onion soup 

Course: SoupsDifficulty: moderate
Servings

6

bowls
Total time

3

hours 

What do you get when you cross french onion, cream of mushroom, and 40 clove garlic soup? This baby is packed with roasted garlic, toasty mushrooms, and caramelized shallot flavor, and the classic french onion cheesy topping takes it to the next level. 

Ingredients

  • Equipment needed
  • Tin foil

  • 2 large baking sheets

  • 5 QT dutch oven (preferred) or stainless steel pot

  • 4 QT pot

  • Immersion blender or small handheld blender

  • For the roasted garlic broth
  • 5 heads garlic

  • 8 cups water

  • 2.5-3 tbsp better than bouillon mushroom base

  • ½ tbsp worcester sauce (sub soy sauce for vegetarian)

  • Salt and pepper to taste

  • For the roasted mushrooms
  • 1.5 pounds mixed mushrooms

  • Olive oil

  • Salt and pepper to taste

  • For the french onion base
  • 4 tbsp of butter

  • 1 yellow onion, thinly sliced

  • 5 large shallots, thinly sliced

  • 2 tbsp finely chopped fresh sage

  • 2 tbsp finely chopped fresh thyme

  • 1 cup white wine or dry vermouth

  • 1 tbsp flour

  • ⅓ cup of cream

  • Salt and pepper to taste

  • For the cheesy bread topping
  • 6 slices of crusty french bread

  • 2 cups grated gruyere cheese (or more to taste)

  • Chopped parsley, for garnish

Directions

  • First, roast the garlic (do this earlier in the day if possible)
  • Preheat the oven to 400 degrees.
  • Cut the top ⅓ off each head of garlic to reveal the inner cloves. Place the heads, cut side up, on two tin foil sheets (2 heads can go on one sheet, and 3 can go on the other). Drizzle the tops of each head with olive oil, then wrap the tin foil completely around the garlic heads so that they are fully enclosed.
  • Place each foil packet on a baking sheet (you can save yourself dishes if you use a large baking sheet here, as you will need one later). Bake until browned and soft, about 40-60 minutes. If you find after 40 minutes that the garlic is still quite pale, open up the foil and let cook uncovered for the next 10-20 minutes.roasted garlic
  • When the garlic is ready, remove from the oven, unwrap, and let cool. Once cool, use your hands to squeeze the garlic cloves out of the skin. Squeeze into a small bowl and set aside.
  • Next, start caramelizing the onions
  • The rest of this recipe starts very much like a classic french onion soup. In a dutch oven or stock pot, melt the butter and add the onions and shallots, along with ½ tsp of salt. Stir, then cover, and let cook over medium low heat for 5 minutes. Remove lid and let onions cook, stirring occasionally, until golden brown and caramelized. Don’t rush this process! It can take anywhere from 40 minutes to 1 hour. If your onions get too brown too quickly, turn the heat down.
  • While the mushrooms caramelize, roast the mushrooms
  • Preheat the oven to 400 degrees. Cut your mushrooms into bite size pieces and spread out evenly across 2 lined baking sheets. Drizzle with olive oil, and season with salt and pepper. Use your hands to coat the mushrooms with the oil and seasonings. Bake until sizzling, about 15-20 minutes, then remove from the oven and set aside. You will use your oven again, so no need to turn it off. roasted mushrooms
  • While the mushrooms roast and the onions caramelize, make the roasted garlic broth
  • Heat the 8 cups of water in a 4 QT pot, and add 2.5-3 tbsp of better than bouillon mushroom base. When the broth is warm, add the Worcester or soy sauce and then the roasted garlic mash.
  • Use an immersion blender to emulsify the garlic into the liquid. If you don’t have an immersion blender, add the garlic to a small blender along with 1-2 cups of warm broth and puree until smooth, then add the mixture back to the pot. If your mushrooms release any liquid during the cooking process, feel free to drain that liquid directly into your broth pot as well. Taste and adjust seasoning as needed. Remove from heat and cover to keep warm.
  • Finally, finish the soup and make the toasted bread and cheese topping
  • When the onions are caramelized and the mushrooms are roasted, add the mushrooms, along with the sage and thyme, to the onion pot and saute for 3 minutes.
  • Add the wine and bring to a boil, stirring regularly, for about 2 minutes.
  • Add the flour and stir to combine, let thicken for 1-2 minutes.
  • Slowly add in the warm stock, stirring to combine. Bring to a simmer and let bubble for about 10 minutes.
  • While the soup simmers, remove the parchment or foil from the mushroom baking sheet and place your bread slices on the baking sheet.
  • Bake at 400 for about 10 minutes until very dry. Remove the bread from the oven and set the temp to broil.
  • Add the cream to the soup and let simmer for a minute, before removing from heat. Taste and adjust seasoning as needed.
  • Ladle the soup into oven safe bowls or ramekins and top with a bread slice and lots of shredded gruyere cheese. Place the bowls on a baking sheet and broil until the cheese is melted and brown, a minute or two. If you don’t have oven safe bowls, you can simply broil cheese on the toast directly, then place the cheesy toasts in each bowl.
  • Top with chopped parsley and serve. roasted garlic mushroom and onion soup
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