Season the boneless chicken thighs with salt and pepper, ensuring even coverage to enhance flavor. Sear the chicken for 2-3 minutes on each side until golden brown, then transfer it to the crockpot.

Sauté chopped onion and minced garlic over medium heat for about 3-4 minutes until soft and fragrant. Add the sautéed mixture to the crockpot on top of the chicken.

Slice your favorite mushrooms and low-carb veggies like zucchini or spinach. Add them to the crockpot, distributing them evenly over the chicken.

Combine Marsala wine and heavy cream in a bowl, then pour the mixture over the chicken and veggies in the crockpot.

Cover the crockpot and cook on low for 6-8 hours or high for 3-4 hours. It's ready when the chicken is tender.

About 15 minutes before serving, check the sauce's consistency and uncover for thickening if needed. Sprinkle with fresh parsley and parmesan cheese before serving.