The secret to this steak soup recipe is the mushrooms! I use three types and they give this beef mushroom soup richness and depth of flavor.
Begin making this steak soup by melting the butter in a large stockpot over medium-high heat, adding the mushrooms, and cooking with a pinch of salt until the mushrooms release their juices.
Reduce heat to low and continue to cook, stirring often until juices evaporate and the mushrooms are golden brown, about 10 minutes. Reserve 1 cup of the cooked mushrooms and set aside.
Add the onion to the stockpot and cook until soft and translucent, about 5 more minutes.
Stir flour into mushroom/onion mixture and cook, stirring often, for a few minutes.
Add thyme, garlic, and chicken stock, bring the steak soup to a simmer and cook for 1 hour.
Remove thyme stalks, transfer soup to a blender in small batches, and puree until smooth and thick.
Return the steak soup to pot and stir in cream, the reserved mushrooms, and beef. Season to taste with salt and black pepper and garnish with fresh thyme leaves.
Make it Keto: Use Almond Flour in place of regular flour. The rest is already low carb.