Preheat the oven to 400 degrees F.
Remove the woody ends of the asparagus spears trimming the spears to the same length.
Bundle 3 asparagus stalks together and wrap each grouping with one slice of prosciutto, leaving the tips exposed. Drizzle the bundles with olive oil.
Roast the bundles for 10 minutes, or until the asparagus ends and the prosciutto slices are crisp.
Drizzle each prosciutto-wrapped asparagus bundle with the prepared beurre blanc and serve.
To make beurre blanc:
Bring the shallots, vinegar, and wine to a boil in a heavy-bottomed saucepan until the liquid is reduced to 2 tablespoons, about 5 minutes.
Add the cream, salt, and pepper and bring to a boil for 1 minute. Reduce the heat to low and whisk in a few tablespoons butter. Continue to whisk and add a few pieces at a time of the remaining butter. Wait until each addition is incorporated before adding more butter. The sauce should remain warm, but never hot or the sauce will break.
Remove the sauce from the heat and season with salt, and pepper, to taste. If desired, strain the sauce through a sieve to remove the shallot. Discard the shallot. Serve the sauce immediately.
Beurre Blanc Variations:
Beurre Rouge: Replace the white wine in the original recipe with red wine and the white wine vinegar with red wine vinegar.
Beurre Citron: Replace the vinegar and wine in the original recipe with 1/4 cup citrus (lemon, lime, and/or orange) juice and add 1 teaspoon citrus zest.
Lime-Ginger: Replace the vinegar in the original recipe with an equal amount of lime juice and add 1 teaspoon minced fresh ginger.
Saffron: Add a pinch saffron threads to the reduction.