Don't let its name fool you--these roll-ups are worthy of a special occasion and call for using one of the leaner cuts of beef, top-round steak.
Preheat oven to 350 degrees. Place slices of steak between two pieces of plastic wrap, and pound to an even thickness; set aside.
In a large skillet, heat 1 tablespoon butter and 1 tablespoon oil over medium-high heat. Add chopped onions, and cook until translucent. Add mushrooms; season with salt and pepper. Cook until the mushrooms have released all of their liquid and it has evaporated. Stir in parsley. Transfer to a small bowl; set aside.
Place one piece of steak on work surface. Spoon 1/6 of the filling onto the center of the steak. Sprinkle with 1/6 of the breadcrumbs. Roll up steak to enclose filling. Tie each end with a piece of kitchen twine. Repeat with remaining steak, filling, and breadcrumbs.
In the same large skillet, heat 2 tablespoons olive oil and 2 tablespoons butter. Add roll-ups, and cook until browned on all sides, about 4 minutes. Transfer roll-ups to a baking dish just large enough to hold them in a single layer.
In a small saucepan, heat remaining tablespoon butter and remaining 2 tablespoons olive oil over medium-high heat. Add garlic and sliced onions. Cook until onions are translucent, about 2 minutes. Stir in tomato sauce and wine. Cook until heated through. Pour over roll-ups and bake, covered, until tender, about 1 1/4 hours. Remove twine, and serve with grated beets and buckwheat groats.