Snap off hard ends of asparagus and toss with olive oil, salt, pepper, and red pepper flakes.
Lay out asparagus on a baking sheet and bake at 400 degrees Fahrenheit for 10-12 minutes until they are bright green, slightly crunchy still, but cooked through. Keep warm until serving.
For the Bearnaise sauce:
Combine vinegar, 2 tablespoons fresh minced tarragon, shallot, and crushed peppercorns in a small saucepan. heat over medium heat until the mixture reduces by half.
In a medium mixing bowl, whisk together water, lemon juice, and salt. Strain in the vinegar mixture and use a spatula to press the liquid through the mesh strainer.
Whisk yolks into the mixture. Place yolk mixture over a double boiler (I just use a small pan with simmering water). Whisk the yolks constantly as they heat until the yolks are doubled in size and foaming. Be careful not to cook the eggs!
Once the yolks are foaming, start whisking in melted butter. Start with just a drop or two of butter and whisk it in. Once the emulsion starts to hold, you can whisk in the rest of the butter in a steady stream though. If it looks really thick at any point, whisk in a teaspoon of cold water.
Once the sauce is made, serve immediately or store the sauce with some plastic wrap on the surface for up to an hour or two.