Preheat oven to 425°F (220°C). Toss hash browns with olive oil, salt, and black pepper. Spread on a baking sheet and bake for 20-30 minutes until golden brown and crispy.

Bake beef bacon on a foil-lined baking sheet at 400-425°F (200-220°C) for 15-20 minutes until crisp. Crumble into pieces once cool.

In a double boiler, whisk together egg yolks, Dijon mustard, vinegar, and lemon juice until thickened (3-5 minutes). Gradually whisk in melted butter until glossy. Add cayenne and salt.

Poach eggs in simmering water with a splash of vinegar for 3-4 minutes until whites are set. Use a slotted spoon to remove and drain on a paper towel.

Divide hash browns into serving dishes. Top with cheeses, ladle gravy over, add crumbled bacon, poached eggs, and drizzle with hollandaise. Garnish with chives or parsley.