Place a pot with about an inch of water on the stovetop and bring to a light boil.

If you don’t have a double boiler, make sure you have a stainless steel bowl that is just big enough to fit in your pot without touching the bottom.

Whisk the egg yolks and lemon juice together in a stainless steel bowl until the mixture has doubled in volume.

Rest the stainless steel bowl on the pot and whisk rapidly. Do not let the eggs get too hot or they will scramble.

Slowly add chunks of the butter or ghee to the egg mixture - whisking constantly.

Once the sauce has thickened, remove from heat and whisk in sea salt.

Cover and place in a warm spot until eggs are cooked.

If your sauce gets too thick before serving, add a few drops of water to loosen it back up.

Bring water and vinegar to a light boil, reduce heat so water is at a simmer.

Meanwhile, crack eggs into a small bowl or individual ramekin.

One at a time, gently tip the eggs from the bowl/ramekin into the simmering water.

Set timer for 3 minutes.

In the meantime, layer the toast and smoked salmon (if using) with the avocado and tomato. You should have four layered servings.

Using a slotted spoon, remove eggs from pot and place on a paper towel to drain. Blot up any excess water.

Place one egg on one layered serving.

Pour hollandaise over top. Serve immediately.