Place 2-3 in. of water in a large skillet with high sides; add vinegar. Bring to a boil; reduce heat and simmer gently. Break cold eggs, one at a time, into a custard cup or saucer. Holding the cup close to the surface of the water, slip each egg into water. Cook, uncovered, until whites are completely set and yolks begin to thicken (but are not hard), about 4-5 minutes.

Meanwhile, in a small saucepan, melt butter over medium heat; whisk in milk and sauce mix. Bring to a boil. Reduce heat; simmer, uncovered, for 1 minute or until thickened. Stir in jalapeno. Set aside and keep warm.

With a slotted spoon, lift each egg out of the water. On each muffin, half layer the Canadian bacon, tomato, avocado and an egg; spoon sauce over tops. Serve immediately.