Heat a large saucepan of water on the stove until just shy of a simmer.
Make the hollandaise: Using a heatproof bowl in the microwave or over a double boiler, melt the ghee until warm to the touch. Meanwhile, add the egg yolks, lemon juice, salt and turmeric to the bowl of a blender. Puree until combined. With the cap off the top and the blender running on medium, slowly stream in the hot ghee. Begin with just a few drops and slowly add the rest until fully incorporate, thick and creamy. The hollandaise should easily coat the back of the spoon but be looser than aioli. Taste for seasoning and add more salt or lemon juice as necessary. Set aside in the blender until ready to assemble, as you may want to pulse again before serving if a skin forms on the top.
Poach the eggs in your gently simmering water using your favorite technique. Mine is this control freak method, but it takes a little longer. Transfer the poached eggs to a towel-lined plate.
Toast or reheat your buns or English muffins, then begin assembling the benedict. In a medium mixing bowl, toss the mixed greens with the lemon juice, olive oil and season with salt and pepper. Top the buns with a small handful of greens (any extra can be served on the side), followed by the sliced avocado and salmon. Top with the poached eggs and drizzle with the hollandaise. Season with salt and pepper and serve immediately.