Step 1: Season the chicken thighs generously with salt and black pepper.
Step 2: Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Sear the chicken thighs, skin-side down, for 5-7 minutes until the skin is golden brown. Flip and sear for another 2-3 minutes. Remove chicken from the skillet and set aside.
Step 3: In the same skillet, add the remaining 1 tablespoon of olive oil. Add the chopped yellow onion and cook for 3-5 minutes until softened and translucent. Add the minced garlic and cook for another minute until fragrant.
Step 4: Add the sliced mushrooms to the skillet and cook for 5-7 minutes, stirring occasionally, until they have released their liquid and started to brown.
Step 5: Pour in the dry white wine (or extra chicken broth) and scrape up any browned bits from the bottom of the pan with a wooden spoon.
Step 6: Sprinkle the flour over the vegetables in the skillet and stir constantly for 1 minute to cook off the raw flour taste.
Step 7: Gradually whisk in the 1.5 cups of chicken broth until smooth. Stir in the dried thyme and bay leaf. Bring the mixture to a gentle simmer, stirring until it begins to thicken slightly.
Step 8: Carefully transfer the sautéed vegetable mixture and thickened broth from the skillet into the bottom of your slow cooker. Place the seared chicken thighs on top of the vegetables.
Step 9: Cover the slow cooker and cook on LOW for 6-8 hours or on HIGH for 3-4 hours, until the chicken is fork-tender and cooked through.
Step 10: Once the cooking time is complete, remove the bay leaf. Stir in the heavy cream until thoroughly combined. Serve immediately, garnished with fresh parsley.