In saute pan over medium heat, brown Italian sausage. Add Panko breadcrumbs and continue to cook until breadcrumbs are golden brown. Set aside so they can cool.

Add 1 Tbsp butter to pan over medium heat. Add onions and cook until soft. Add spinach and cook until fully wilted. Salt and pepper to taste. Squeeze out excess liquid. Mix in cream cheese and parmesan cheese and set aside to cool.

Clean and chop mushrooms. Melt 1Tbsp butter in pan over medium heat. Add mushrooms and thyme. Cook until mushrooms are browned. Salt and pepper to taste. Set aside to cool.

Prepare tenderloin by trimming excess fat, cut 3/4 through lengthwise. Place between plastic wrap and flatten with meat mallet.

Layer stuffing ingredients in the following order: Sausage mixture, Spinach mixture then mushrooms. Leave about an inch around the edges so stuffing won't spill out while rolling.

Roll tenderloin lengthwise as tightly as possible. Use the plastic wrap to help with this process. Once rolled, wrap tightly with plastic wrap and refrigerate about 15 minutes. Refrigerating will help it hold together while wrapping with bacon.

Wrap with bacon. Starting at one end wrap tightly, adding new slice at end of previous slice. Add generous sprinkle of black pepper. Again, wrap tightly in plastic wrap and refrigerate 15 minutes.

Preheat oven to 375 F. Remove plastic wrap and place in oven proof dish. Cover with foil and bake 20-30 minutes. Remove foil and bake an additional 5-10 minutes until bacon is crisp and internal temperature is 140°-145° F.

Let rest 10 minutes before slicing and serving. Enjoy!