3/4 pound russet potatoes, peeled, cut into 1-inch cubes
1 tablespoon butter, room temperature
1/4 cup heavy whipping cream, room temperature
2/3 cup coarsely shredded Gruyère cheese (about 3 ounces), divided
Directions
Melt butter in large skillet over medium heat. Add shallots; sauté until beginning to brown, about 6 minutes. Add flour; stir 1 minute. Add Madeira, then braising liquid. Whisk until mixture thickens and boils, about 3 minutes. Stir in beef and vegetables. Season with salt and pepper. Keep warm. DO AHEAD Can be made 1 day ahead. Cool slightly. Cover; chill. Rewarm over medium heat.
Preheat oven to 375°F. Boil parsnips and potatoes in medium saucepan of salted water until tender, 12 minutes. Drain. Return to saucepan. Cook over medium heat until dry, about 1 minute. Add butter and cream; mash until smooth. Stir in 1/3 cup cheese. Season with salt and pepper.
Transfer filling to 8x8x2-inch baking dish. Spread topping over filling. Sprinkle remaining cheese over. Bake until bubbling and top begins to brown, about 30 minutes.