Begin by grating the russet potatoes and yellow onion directly into a bowl filled with salted water. Allow them to soak for 20 to 30 minutes; this step helps to remove excess starch and prevents browning.

In a clean mixing bowl, combine the drained potato and onion mixture with a lightly beaten egg, matzo meal (or all-purpose flour), and your desired seasonings of kosher salt and black pepper. Mix thoroughly until everything is well incorporated.

Add vegetable oil to a large skillet and heat over medium heat until it shimmers. To test, drop a small spoonful of the latke mixture into the oil.

Using a spoon, drop 3-4 tablespoons of the latke mixture into the hot oil, shaping them into approximately 3-inch rounds. Fry the latkes for 6 to 10 minutes on each side.

While your latkes are frying, bring a saucepan filled with water and a splash of white vinegar to a gentle simmer. Carefully crack large eggs into the simmering water and poach them for 4½ to 5 minutes.

In a blender, combine egg yolks, fresh lemon juice, and a pinch of salt. Blend until it lightens in color and thickens slightly. Slowly drizzle in melted unsalted butter until creamy.

On a warm plate, place a crispy latke as the base. Top it with a slice of smoked salmon, followed by a perfectly poached egg. Drizzle the hollandaise sauce over the egg and sprinkle fresh chives or diced red onion.