In a skillet, melt butter over medium-high heat; cook mushrooms, garlic, onion, rosemary, salt and pepper, stirring for 10 minutes or until liquid is evaporated and mushrooms are browned. Transfer all but 1/2 cup to a bowl for stuffing; cool, cover and refrigerate for up to 1 day.
Add wine to skillet; cook, scraping up bits stuck to pan. Pour in 1 cup cream; simmer for about 5 minutes, stirring often, until reduced. Cool, cover and refrigerate for up to 1 day.
Preheat oven to 325°F Add remaining 1/4 cup cream and bread crumbs to stuffing; stir to combine. Place turkey breast, skin side down on work surface. Press stuffing on surface, leaving about 1/2" border. Roll up jelly-roll style; secure with kitchen string or toothpicks.
Place seam side down in roasting pan. Bake for about 1-1/2 hours, basting occasionally, until meat thermometer reads 170°F Transfer to cutting board; tent with doil and let rest for 15 minutes.
Meanwhile, return sauce to saucepan over medium heat; reheat until bubbling. Slice turkey; spoon sauce onto plates and top with turkey slices.