Put black garlic cloves into a small bowl and mash with a fork until smooth.

Wipe any dirt from mushrooms using a damp paper towel. Slice mushrooms.

Season chicken breasts with salt and pepper on each side.

Melt butter and 1 tablespoon olive oil in a 12-inch nonstick skillet over medium-high heat.

Add chicken and cook until browned on both sides, about 4-5 minutes on each side. Test chicken temperature with an instant read thermometer (it should read 165° Fahrenheit). If chicken is not done, continue to cook for another minute or two on each side until it is fully cooked. Remove chicken from pan and set aside on a plate, tented with aluminum foil to keep warm.

Add another tablespoon of oil to the skillet, then add sliced mushrooms.

Sauté mushrooms until browned, about 5-8 minutes, stirring occasionally. Adjust the heat if you need to, turning it down a little if the mushrooms are browning too quickly. Remove mushrooms from pan and set aside in a bowl separate from the chicken—you will add the mushrooms to the sauce later.

Turn heat down to medium if you haven’t already.

Pour a small amount of heavy cream into the skillet along with the mashed black garlic cloves. Whisk to combine mashed black garlic cloves with cream. When the garlic has mostly dissolved, add the rest of the heavy cream, chicken broth, and 2 teaspoons lemon juice to the skillet.

Simmer, stirring frequently with your whisk, until sauce thickens slightly and garlic fully dissolves, about 2-4 minutes. Taste sauce and add the additional teaspoon of lemon juice to taste. Season with salt and pepper to taste.

Stir mushrooms back into sauce.

Move chicken breasts onto serving plates and top with mushroom black garlic sauce.

Garnish with chopped parsley or chives, if desired.