This combination of oyster mushrooms and asparagus hits the spring vegetable sweet spot. Raleigh, NC chef Ashley Christensen adds cream and finishes with porcini butter, a flavorful compound butter you should make in advance. It’s an optional addition, but its earthy punch makes this dish a knockout.
In a large skillet, heat 1 tablespoon oil over medium heat until shimmering. Add mushrooms to the pan in an even layer. Sear, stirring a few times, until the moisture from the mushrooms has evaporated and the edges begin to crisp, 1–2 minutes. (If the pan seems dry as the mushrooms cook, add remaining ½ tablespoon oil.) Add the shallots and thyme; stir to coat and cook, 1 minute. Add asparagus and a pinch of salt, and continue cooking until the asparagus are bright green and slightly soft, 1–2 minutes depending on asparagus size.
Add sherry and swirl the pan until the liquid has reduced by ¾. Add heavy cream and let it reduce until it has thickened slightly, 2 minutes. Stir in one tablespoon of butter and one tablespoon of porcini butter, and continue sautéing until the sauce coats the vegetables, 1 more minute. Turn off heat. Taste and adjust seasoning with salt if necessary, and finish with lemon juice. Serve immediately. Porcini Butter: In a small saucepan combine mushrooms with just enough water to cover them. Bring to a boil; reduce to a simmer and cook on low heat for 45 minutes. Mushrooms should be soft, with a bit of liquid in the pan. Purée mushrooms and remaining liquid with butter until smooth. Transfer to a lidded container and refrigerate until ready to use. Porcini butter can be stored in the refrigerator up to 2 weeks and in the freezer up to 3 months.