Add pancetta to Dutch oven and cook, stirring frequently, over medium-high heat until just crisp. With a slotted spoon, transfer to a plate and set aside.
Season turkey legs with salt and pepper. Add them to the hot oil add brown on all sides for 6-8 minutes. Transfer to plate with pancetta.
Add mushrooms, onions and carrots to the hot oil and cook, stirring, 2 to 3 minutes. Add garlic and cook, stirring for 30 seconds. Add flour and stir to coat everything. Stir in brandy.
Return the pancetta and turkey legs to the pot. Add red wine, broth and thyme bundle. Bring to a boil, reduce to low, cover, and cook until turkey is falling off the bone, about 2-3 hours.
Remove lid and transfer the turkey to a cutting board. Shred or chop the meat discarding the skin and bones.
Remove thyme bundle from pot. Increase heat to medium-high and simmer to thicken sauce a bit 2-3 minutes. Return turkey meat to pot to warm through. Serve over mashed potatoes sprinkled with chopped parsley.