In a large frying pan heat butter and olive oil; add garlic cloves and cook on medium high heat until fragrant, about 1 minute. Add chicken and brown chicken parts on each side until golden.
Season with salt and pepper, add a few spoons of the chicken stock, lower the heat and roast the chicken adding a little broth at a time until cooked all the way through, 30-35 minutes.
When the chicken is cooked, pour the Portobello Mushroom Sauce in the pan and sauté 2-3 minutes more basting the chicken in the sauce. Serve with rice, potatoes or roasted vegetables.