For the sweet potato latkes:
1. Preheat oven to 400 degrees. Using largest holes of a box grater, grate potatoes into a large bowl. Season with salt and pepper and toss to coat. Let sit for 5 minutes, then transfer shredded potatoes to a clean kitchen towel and wring out excess liquid.
2. Transfer potatoes to a medium bowl with egg and flour. Mix thoroughly and form into eight equal-sized patties. Place latkes on a nonstick sheet pan, spacing apart evenly. Drizzle with butter then bake until golden brown and crisp, 15 to 18 minutes. Keep warm until ready to serve.
For the scallion hollandaise:
1. In a medium saucepan, bring 2 cups water to a slow simmer. Place a medium stainless steel bowl over top to create a double boiler.
2. Add egg yolks and lemon juice to bowl and whisk constantly until mixture starts to steam and is thick like a yellow cloud. Slowly whisk in melted butter and scallions. Add hot sauce and salt to taste. Keep warm until ready to serve.
For butter-poached shrimp:
In a medium saucepan, bring 3 tablespoons water to a boil. Reduce heat to very low and whisk in butter piece by piece until emulsified. Add lemon juice, salt, cayenne, and garlic. Add shrimp and poach for 8 minutes, then remove from heat. Keep warm until ready to serve.
For the poached eggs:
1. Prepare a half sheet pan with a layer of paper towels. In a large saucepot, bring 1 gallon water and vinegar to a simmer.
2. Using a slotted spoon, stir water in a clockwise direction, then drop eggs in one by one while water is still rotating. Allow eggs to cook for 3 minutes, then, using the slotted spoon, carefully transfer to the sheet pan. Trim away any excess egg white.
Place two latkes on each plate and top each latke with shrimp. Top shrimp with a poached egg, spoon scallion hollandaise over top, and garnish with scallions. Serve immediately.