In a large bowl, combine diced potatoes (both kinds), olive oil, cumin, sea salt, pepper, and garlic powder. Toss to coat the potatoes with oil and spices.
Line a baking sheet with parchment paper then spread the potatoes out on the sheet so that they are in one even layer.
Roast the potatoes until they are brown, crispy and cooked through... About 30-35 minutes.
While the potatoes are roasting, make your hollandaise sauce (instructions below).
After the hollandaise sauce is made, start the egg poaching process! you should follow these instructions if you haven't poached an egg before. I would start boiling your water when the potatoes have about 5 minutes left.
Once the potatoes are cooked to your liking, remove them from the oven and place in a large bowl with the 2 cups of baby spinach. Mix the spinach and potatoes together and let sit for several minutes so the spinach can wilt slightly (you should now start poaching your eggs in the water that is hopefully boiling from step 6).
To serve, divide potato spinach mixture evenly between four shallow bowls or plates then top with one poached egg and a generous drizzle of hollandaise sauce!
In a small sauce pan over low heat, melt butter. Do not let it brown. Remove from heat once melted.
Combine egg yolks, sea salt, cayenne pepper, and lemon juice (start with 2 tablespoons) in a blender and blend at a slow speed. Slowly drizzle the melted butter into the blender until it's totally incorporated into the sauce and the sauce has thickened.
Taste and add more lemon juice, sea salt, and/or cayenne pepper if needed.
Transfer hollandaise sauce to a container and keep warm until hash is ready.