Preheat oven to 375°F. Grease a baking dish with butter.
Season chicken all over with salt, lemon pepper and paprika. Sear chicken in a hot skillet to lock in juices, then transfer to baking dish and bake for 15-20 minutes.
Make creamed spinach: In a skillet, wilt spinach with vegetable oil for 1-2 mins. Remove from heat and stir in garlic and half and half. Bring to boil then add mozzarella, stirring constantly until sauce is creamy and smooth. Season with salt.
Sauté mushrooms in oil over high heat for 1-2 mins until caramelized.
Remove chicken from oven and top each breast with creamed spinach, bacon bits, sautéed mushrooms and pepper jack cheese slices.
Return to oven for 15-20 more minutes until chicken is fully cooked. Broil for 2-4 minutes to brown the cheesy tops.
Let rest 5 mins before serving hot. Enjoy!