Prepare the Marinade:
In a small bowl, combine Dijon mustard, honey, mayonnaise, and lemon juice. Set aside ¼ cup of the marinade in a covered container in the refrigerator for serving.

Marinate the Chicken:
Place the chicken breasts in a large plastic zipper-top bag. Pour the remaining marinade over the chicken and ensure it’s evenly coated. Refrigerate for 30 minutes, or overnight for deeper flavor.

Cook the Chicken:
Preheat the oven to 400°F (200°C). In a large oven-proof skillet, melt butter over medium-high heat until the foam subsides. Add sliced mushrooms and sauté until they release their moisture and begin to brown, about 5-7 minutes. Remove mushrooms and set aside. In the same skillet, heat olive oil and cook the marinated chicken breasts for about 5 minutes per side until golden-brown crust forms.

Add the Toppings:
Top each chicken breast with sautéed mushrooms and shredded Colby Jack cheese. Cover the skillet and transfer it to the oven.

Bake:
Bake for about 10-15 minutes, or until the chicken reaches an internal temperature of 165°F (74°C).

Garnish and Serve:
Garnish with fresh parsley (optional) and season with salt and black pepper to taste. Serve with the reserved marinade on the side for dipping.