Mushroom Hollandaise Recipe

Cook onions low and slow

Heat 1 tbsp butter and 1 tsp olive oil in a medium skillet over medium-low heat. Add the thinly sliced yellow onion and 1/4 tsp salt. Cook, stirring every 3–4 minutes, until soft and deep golden brown, 20–30 minutes. Add 1 tsp brown sugar about halfway through if you want a slightly sweeter, faster caramelization. When done, remove from pan and keep warm.

Brown mushrooms

In a hot wood-oven-safe skillet or cast-iron pan, add 1 tbsp olive oil and 1 tbsp butter over medium-high heat. Add chopped mushrooms and a pinch of salt. Cook without overcrowding, stirring occasionally, until mushrooms release their liquid and it evaporates and the edges brown, about 6–8 minutes.

Add aromatics and spinach

Reduce heat to medium, add minced shallot and garlic to the mushrooms and sauté 1–2 minutes until fragrant. Add 2 cups spinach and cook until wilted, 1–2 minutes. Season with 1/2 tsp salt and 1/2 tsp black pepper. Remove mushroom-spinach mixture to a bowl and keep warm.

Prepare a double boiler

Set a heatproof bowl over a pan of barely simmering water (water should not touch the bowl). Whisk 3 egg yolks with 1 tbsp lemon juice and 1/2 tsp salt until slightly thickened and pale, about 1–2 minutes.

Emulsify with butter

Very slowly, in a thin stream, whisk in the 6 tbsp hot melted butter until the sauce thickens and becomes glossy. If the sauce gets too thick, whisk in up to 1 tsp hot water to loosen. Off the heat, whisk in 1 tsp Creole seasoning and adjust salt/lemon to taste. Keep warm but not hot (cover and place near the oven).

Whisk eggs for fluffiness

Crack 6 large eggs into a bowl, add 2 tbsp whole milk, 1 tsp salt, and 1 tsp black pepper. Whisk vigorously until fully combined and slightly frothy, 30–45 seconds. This produces a country-style fluffy texture.

Cook the omelet

Heat the skillet (same one used for mushrooms if clear, or a clean 10–12 inch cast-iron skillet) over medium heat and add 1 tbsp butter. When butter foams, pour the beaten eggs into the pan, tilting to spread evenly. Let eggs set undisturbed for 20–30 seconds, then using a spatula gently push edges toward center allowing uncooked egg to flow underneath. When eggs are mostly set but still slightly custardy on top (about 1–2 minutes), sprinkle the cooked mushroom-spinach mixture across one half of the omelet, add the caramelized onions, and evenly top with 3 oz grated Swiss cheese.

Finish under wood oven or broiler (optional)

If you have a wood oven, place the skillet in the oven briefly (or under a preheated broiler) for 1–2 minutes to finish the top and melt the cheese and to impart a slight char. Watch closely to avoid overcooking. Otherwise cover the skillet with a lid for 1–2 minutes until cheese melts and eggs finish cooking.

Fold and plate

Gently fold the omelet in half over the fillings and slide onto a warm plate. Spoon 3–4 tbsp of the warm Creole Hollandaise over the top.

Scatter chopped chives over the hollandaise, grind a little fresh black pepper, and serve immediately.