Asparagus & Mushroom Frittata

Preheat the oven to 400°F. Line two rimmed baking sheets with parchment paper. Cut the top two inches off the asparagus stalks. You will only use the tips. The rest of the asparagus stalks can be cooked or used in salads.

Toss the asparagus tips with two-thirds of the vegetable oil and sprinkle lightly with salt. Spread on one of the prepared baking sheets. Repeat with the mushrooms, using the other third of the oil. Roast the vegetables until lightly browned, about eight minutes. Let cool completely.

Heat the butter over medium-high heat in a 12- to 14-inch nonstick sauté pan with an ovenproof handle. Make sure the butter touches every side of the pan. Reduce the heat to medium, add the mushrooms and asparagus, and cook for 30 seconds. Add the eggs. Gently stir the eggs and vegetables with a rubber spatula.

When the eggs are halfway cooked, stop stirring and let the frittata form, about five minutes. A little bit of color on the bottom is fine. Turn the oven to a low broil setting and finish cooking the frittata in the oven. This should take no longer than five minutes. Remove the frittata from the oven and let it rest for five minutes before serving.

For the pickled red onion:

Combine all of the ingredients in a nonreactive saucepan and bring to a boil. Turn off the heat and let the onions cool completely. The onions are ready to serve once cooled. The onions can be refrigerated in their liquid for up to seven days. 

For the whipped feta:

Combine all of the ingredients in the bowl of a stand mixer fitted with the paddle attachment. Mix on medium speed until smooth. Cover and refrigerate until ready to use. Any leftover whipped feta can be refrigerated for up to seven days. 

To serve: Spoon the whipped feta onto the frittata. Drain the pickled onions and place on top. Cut the frittata into six pieces and remove them with a pie server.

(Note: You can also bake the frittata in a nine- by 13-inch ovenproof glass casserole dish. To help prevent sticking, coat the dish with cooking spray. Sauté the roasted vegetables in the butter in a skillet. Combine the vegetables and eggs in the casserole dish, and bake in a 350°F oven for 35 minutes. Check the center with a toothpick to see if it is cooked completely. Let it rest for five minutes before cutting.)