You can add any spice you want to jazz up the classic sauce
We learned how to make a hollandaise on the second day of my culinary program. It's a notoriously tricky sauce: If you don't have the temperature of the egg yolks and clarified butter right, you can either end up with scrambled eggs in butter (could be worse) or standing over the stove for an hour, whisking hopefully. The good news is that there's no reason why you need to use the traditional double boiler method unless you just love a challenge. Hollandaise tastes just as good made in a blender. Or, as our chef instructor taught us, you can make it the same way you might a lemon curd: add lemon juice, butter, egg yolks (about 2 for every stick of butter), and spice all at once, warm it slowly on your stove while whisking constantly, and voila—a hollandaise appears.
Traditionally, you add a bit of cayenne to the ingredients to give it a tiny kick, and that got me thinking. You know what spices go well with butter and egg yolks? Most of them. If you substitute the cayenne with, say, ras al hanout or Aleppo pepper or taco seasoning or za'atar, would the hollandaise be good? Would it get me permanently barred from France? I had to find out.
Using the easier, lemon curd-adjacent stovetop method described above, I added a pinch of taco seasoning to my hollandaise at the beginning, maybe 1/4 of a teaspoon, though you can always add more if you'd prefer. I whisked until the sauce thickened and poured it over some eggs I'd fried and, dear reader, it was every bit as delicious as I thought it would be.
I also tried it with Aleppo pepper, and since it's not quite as strong as cayenne, I added close to a whole teaspoon for a lovely rounded peppery note. (You can adjust depending on your tolerance for spice, of course.) The only real failure I had was with cumin. I added too much at the beginning and the smokiness overpowered the pleasant richness of the sauce. But you could try any spice that plays well with eggs. Sichuan peppercorns would be interesting! Garam Masala would probably be intensely delicious, particularly served over an egg on a bed of crispy chickpeas. I mean, you could absolutely try Ranch dressing powder and see how it works out. Talk about dirtbag fancy.
1/4 cup or 1 stick of butter, cut into chunks
2 egg yolks
Lemon juice, to taste (I used about 1 tablespoon)
1/4 to 1/2 teaspoon of taco seasoning (or Aleppo pepper, Ras al Hanout, etc., etc.)
Salt, to taste
Put the egg yolks, butter, lemon juice, and taco seasoning in about a two-quart saucepan over medium-low to low heat. Whisk until the butter melts, and then bump the heat down a tad lower, still whisking constantly, until the sauce thickens. You want a consistency that would coat the back of a spoon. Add salt to taste. Serve on everything.