In a large, heavy skillet, melt 1 tablespoon butter over medium-high heat. Season 2 steaks with salt and pepper and add to the pan, weighting them down with a Dutch oven or another skillet. Cook until browned, about 1 1/2 minutes per side. Transfer the steaks to a large platter, cover loosely with foil and repeat with another tablespoon butter and the remaining 2 steaks.
In the same skillet, add the mushrooms, shallots and garlic. Cook, stirring frequently, until the mushrooms are softened and the shallots are translucent, about 5 minutes. Reduce the heat to medium, add the beer and simmer until the liquid is reduced by half, about 3 minutes. Remove from the heat and whisk in the remaining 1 tablespoon butter and the Worcestershire sauce. Top each steak with the mushroom mixture.