Step 1

Heat a large soup pot or Dutch Oven (I like my 7.25 quart Le Creuset Enameled Dutch Oven) over medium-high heat. Once hot, add 2 Tablespoons butter and allow to melt. Add mushrooms then stir to coat in butter and saute until the mushrooms release their liquid, the liquid cooks off, and they begin to turn golden brown, 8-10 minutes, stirring often and turning the heat down slightly if they begin to burn. Add garlic and season with salt then continue to saute until the mushrooms are deep golden brown and become dry/tacky, 7-8 more minutes. Scoop into a bowl or plate then set aside.

Step 2

Turn heat down to medium then melt remaining 2 Tablespoons butter in pot. Add carrots, celery, and shallot/onion then stir to coat in butter and season with salt and pepper. Saute until tender, 8-10 minutes, placing a lid on top of the pot to speed up the softening process if the vegetables are taking a long time to cook. Add dried thyme then saute for 1 more minute.

Step 3

Add rice, chicken stock, and cooked mushrooms into the pot then stir to combine. Turn heat up to high to bring mixture to a boil then place a lid on top, turn heat down to low, and simmer until rice is tender, 45-60 minutes (depending on the brand you use), stirring occasionally.

Step 4

In a small dish, whisk together flour and 1/4 cup milk until smooth. Add remaining 3/4 cup milk then stir to combine, and then stream mixture into soup and stir well. Simmer, uncovered, for 10 more minutes. Remove pot from heat then let sit and thicken for 20 minutes. Taste and add additional salt and pepper if necessary then scoop into bowls and serve.