Begin by grating the russet potatoes and yellow onion using a food processor. Soak the grated mixture in salted water for up to 1 hour.

Drain the potatoes and onion thoroughly, pressing out as much moisture as possible. Combine with beaten egg, matzo meal or flour, and seasonings.

Heat oil in a skillet, form small latke patties, and fry until golden brown and crispy.

Poach the eggs in a pot of gently simmering water with vinegar for about 4½ to 5 minutes.

In a blender, combine egg yolks, lemon juice, and salt. Slowly add melted butter and blend until thickened for hollandaise sauce.

Assemble by placing a latke at the base, topping with salmon, a poached egg, and hollandaise. Garnish with herbs and serve immediately.