Roasted Asparagus with Poached Egg and Lemon-Mustard Sauce

The sauce here can sort of be thought of as a lazy-man's hollandaise, without the massive
amounts of butter. So maybe it's not like hollandaise at all. But, it's lemony and has a mustard kick to it, and the tarragon adds a little herbal note. The thing about this sauce is that it seems like it was way harder to make than it actually was. 

Serves 4

• 1bunch thin asparagus
• 1tablespoon extra virgin olive oil
• 1/4teaspoon plus 1/8 teaspoon kosher salt, divided
• 1/4teaspoon plus 1/8 teaspoon freshly ground black pepper, divided
• 3/4cup heavy cream
• 1 1/2tablespoons fresh lemon juice
• 1tablespoon unsalted butter
• 1/2teaspoon finely chopped fresh tarragon leaves, plus additional for garnish
• 1/4teaspoon lemon zest
• 1/8teaspoon Colman's mustard powder
• 2tablespoons apple cider vinegar
• 4eggs

1. Preheat oven to 425° F. On a rimmed baking pan, arrange asparagus in a single layer. Drizzle with olive oil and sprinkle with 1/4 teaspoon each salt and pepper. Roast 10 to 12 minutes or until asparagus is tender.
2. In small saucepan, heat cream over medium-high heat until just simmering. Reduce heat to medium and simmer 6 to 8 minutes or until cream is reduced to 1/2 cup, or is a thickened, saucy consistency. Remove from heat; whisk in lemon juice, butter, tarragon, lemon zest, mustard powder, and remaining 1/8 teaspoon each salt and pepper. Keep in a warm spot on your stove.
3. Fill a high-sided skillet with water; heat to boiling over high heat. Reduce heat so that water is just barely bubbling. Add vinegar to water. Crack each egg into a small bowl or ramekin and slide egg into water. Poach 3 to 4 minutes or until whites are cooked through but yolk is still soft. Remove eggs from pan and drain on paper towel.
4. Divide asparagus between plates. Top with poached eggs and drizzle with sauce; garnish with additional tarragon.

https://food52.com/recipes/21539-roasted-asparagus-with-poached-egg-and-lemon-mustard-sauce