Melt butter in a medium saute pan for the hash browns over medium heat. Cook according to package directions — most frozen hash browns will take 10-12 minutes with a flip halfway through.
While the hash browns are cooking, set the water in the small pot to boil.
Melt the tablespoon of butter in a microwave safe cup or bowl for the hollandaise sauce.
Separate an egg yolk into a ramekin. Add lemon juice and salt. Set aside. Leave the egg white in a separate ramekin for later.
Stir the hasbrowns if needed.
Pour the melted butter slowly into the egg yolk-lemon mixture while constantly whisking to keep it from cooking the eggs. Whisk whisk whisk. Set aside.
Place the small strainer over a different ramekin and gently crack a whole egg into it. Some of the white will strain through, but not all of it.
Put the vinegar into the boiling water and set the heat to low. Stir up a spoon tornado in the water.
Lift the strainer with the egg yolk and some white from the ramekin, and gently slip it into the swirl of water. Set a timer for 3 minutes and don't touch the egg anymore until the timer goes off.
Plate the hash browns, they should be done by now.
Lift the poached egg from the water using a slotted spoon and place on the hash browns. If the hash browns are not ready, set the poached egg aside on a small plate, carefully.
Stir the hollandaise sauce again and drizzle over the egg and hash browns.
Garnish with microgreens, salt and pepper to taste. Eat immediately.