Pat the chicken breasts dry and season both sides with salt, pepper, and paprika.

Heat olive oil in a large skillet over medium-high heat. Sear the chicken for 2-3 minutes per side until golden brown. Transfer the seared chicken to the bottom of your slow cooker.

In the same skillet, melt the butter. Add the sliced mushrooms and cook until they have browned, about 5-7 minutes. Add the chopped onion and cook for 2-3 minutes until softened. Stir in the minced garlic and cook for another minute until fragrant.

Sprinkle the flour over the vegetables and stir to combine. Cook for one minute.

Gradually pour in the chicken broth, stirring constantly and scraping the bottom of the pan to release any browned bits. Bring the mixture to a simmer and stir in the dried thyme.

Pour the mushroom sauce mixture over the chicken in the slow cooker.

Cover and cook on LOW for 4-6 hours or on HIGH for 2-3 hours, until the chicken is tender and cooked through.

In the last 15 minutes of cooking, stir in the heavy cream and fresh parsley. Let it heat through. Taste the sauce and adjust seasoning with more salt and pepper if needed before serving.