Eggs Benedict is a hallmark of weekend brunches across the country. First poach the eggs; let stand in cold water. Then make the hollandaise and let it stand at room temperature. When muffins and bacon go in the oven, reheat eggs.
Split muffins in half horizontally and arrange in a single layer, cut sides up, on a 14- by 17-inch baking sheet. Lay bacon slices in a single layer in a 10- by 15-inch pan.
In a 450° oven, bake muffins and bacon until browned, 5 to 7 minutes.
Place 2 muffin halves, cut sides up, on each plate. Lay 1 bacon slice on each muffin half; set 1 egg on each slice of bacon. Spoon hollandaise equally over portions. Arrange watercress next to muffins.