FOR THE HASH:

1. Heat olive oil in a very large skillet (my favorite one is ~12" in diameter) over medium-high heat. Add sliced leek and mushrooms and sauté for 3-4 minutes until the vegetables have reduced in size.
2. Add diced potatoes to skillet and stir to combine. Cook potatoes, stirring occasionally, for approximately 10 minutes or until they've cooked through. If the potatoes are sticking to the pan too much, deglaze the skillet with a little bit (1/3 cup or so) of water or chicken stock and continue to cook the potatoes.
3. Add salt and pepper to taste.
4. When potatoes are just about done, poach your eggs in a pot of just-simmering water until the whites have cooked through, about 4 minutes.
5. Top the hash with the poached eggs and top the eggs with another dash of salt and pepper.
6. Top the whole thing with a generous drizzle of hollandaise (recipe below) and a handful of fresh chopped parsley.
7. Serve immediately with a few pieces of toast on the side (we like to use sourdough bread!)

FOR THE HOLLANDAISE:

1. Add egg yolks, lemon juice, and salt to a tall, narrow cup that fits the head of an immersion blender.
2. Melt butter in a saucepan (or in the microwave!) until a thermometer registers a butter temperature of around 200 degrees F.
3. Blend the egg mixture with the immersion blender until egg yolks have lightened in color.
4. Stream hot butter in a little at a time while you run the immersion blender, letting the hot butter cook the eggs and blending until hollandaise is light and fluffy and all butter has been incorporated. If the hollandaise gets too thick, blend in a few teaspoons of water to loosen it before serving.