Mashed Potatoes: In saucepan, bring 1/2 c water, butter and salt to boil; remove from heat. Stir in dehydrated potato flakes and milk; set aside.
Waffles: In large bowl, whisk together flour, baking powder, baking soda, salt and pepper; set aside. In separate bowl, whisk together egg, buttermilk and melted butter until blended. Whisk in mashed potatoes until smooth.
Stir mashed potato mixture into flour mixture (do not over mix). Fold in cheddar and chives; let stand for 10 minutes.
Ladle 1/2 cup batter into waffle iron. Close lid; cook for 2-3 minutes or until waffles are golden and crispy. Repeat with remaining batter. Keep waffles warm in oven.
Poached Eggs: Meanwhile, pour enough water into saucepan to come 3 inches up side; heat until water is simmering gently. Stir in vinegar. Break each egg into small dish; holding dish just above simmering water, slip each egg into water. Cook, in barely simmering water for 3-5 minutes or until the white is set and yolk is cooked to desired doneness. Remove eggs with slotted spoon. Drain well on paper towel.
Serve poached eggs on waffles and sprinkle with chives.
Tip: Alternatively, serve waffles with fried eggs or just a dollop of sour cream or yogurt.