Poached Eggs with Buttery Multigrain Toast

Eggs can be cooked in advance and stored in cold water in the refrigerator, but in this case, be sure to slightly undercook them. Preheat them in hot water before serving.
Preheat the broiler.In a 12-inch skillet, bring a 2-inch layer of water (about 4 cups) to a gentle boil with the vinegar added. Break the egg into the batter pan so that the bubbles wrap around the egg and form the white around the yolks. Add the remaining eggs, then turn down the heat and simmer them until they almost bubble, for 3 minutes or until the desired degree of roasting. To test them, lift the egg with a slotted spoon and press with the tip of your finger: the white should solidify, and the yolk should remain soft. Transfer the eggs to a bowl of warm water. If desired, trim the edges of each egg with kitchen scissors.Spread 1 1/2 teaspoons of butter on each slice of bread. Place the bread slices in a single layer on a thick baking sheet; bake for 3 minutes or until golden brown. Place one slice of toasted bread on each of 4 plates; sprinkle each serving with 1/2 cup arugula and one egg. Sprinkle evenly with salt and pepper and serve immediately.