Step 1

Preheat a large cast-iron skillet over medium-high for 5 minutes.

Step 2

Slice large mushrooms in half lengthwise, leave smaller mushrooms whole.

Step 3

Reduce heat to medium and add oil; swirl to coat pan. Arrange mushrooms in an even layer, as best you can, cut side down. Cook, without moving, for 3 minutes.

Step 4

Season mushrooms with ¼ teaspoon each kosher salt and pepper; toss and continue cooking until golden brown all over, about 5 minutes.

Step 5

Reduce heat to medium-low, add butter, garlic, and nutmeg and cook 2–3 minutes until garlic is toasted.

Step 6

Remove skillet from heat and add parsley leaves and ½ teaspoon zest.

Step 7

Stir to combine then season with additional salt, pepper and lemon zest to taste.