Bring a small pot of water to a boil. Slice and toast the bagels, set aside.
Melt the butter in a large pan over a medium and add the green leaves.
Cover with a lid and cook the greens for 2-3 minutes stirring once or twice until almost wilted.
Season with some salt and black pepper then turn of the heat, keep covered.
Add the vinegar to the boiling water and stir with a spoon vigorously creating a swirling motion in the water.
Quickly drop the eggs into the water making sure they are separated from each other and cook for about 2 1/2 minutes, checking them with a slotted spoon. The whites should be cooked but with a soft yolk.
Transfer the eggs to a paper towel while you construct the bagel. Lay a few slices on the bagel followed by the wilted greens.
Top with a poached egg and finish with the other half of the bagel. Serve at once.