Asparagus with Osetra Caviar

SERVES 4

When making this elegant dish, chef Philippe Rochat often uses asparagus from the town of Pertuis, in Provence, and garnishes the caviar with purple statis flowers. Serve any leftover mousseline sauce over steamed vegetables or fish.

FOR THE COCKTAIL SAUCE:
2 tbsp. ketchup
2 tsp. dijon mustard
2 tsp. cognac
1 tsp. red wine vinegar
1 egg yolk
1⁄3 cup grapeseed oil
Salt and freshly ground white pepper

FOR THE ASPARAGUS:
Salt
12 thick stalks asparagus
1 tbsp. hazelnut oil
2 oz. osetra caviar
12 fresh chervil leaves

FOR THE MOUSSELINE SAUCE:
1 tbsp. dijon mustard
1 tsp. white wine vinegar
1 egg yolk
1 cup grapeseed oil
3 tbsp. heavy cream, whipped
Salt and freshly ground white pepper

1. For the cocktail sauce: Whisk ketchup, mustard, cognac, vinegar, and egg yolk together in a medium bowl. Pour in oil in a steady stream, whisking constantly, to form a smooth sauce. Season with salt and pepper to taste and transfer sauce to a squeeze bottle with a fine tip. Refrigerate until ready to use.

2. For the asparagus: Bring a large pot of salted water to a boil over high heat. Add asparagus and cook until just done, about 2 minutes. Using tongs, remove asparagus from pot and transfer to a large bowl of ice water. Reserve 1⁄2 cup of the cooking water. When asparagus is cold, remove stalks from water and blot them dry. Trim each stalk on the bias to a length of about 5". Cut out a 1 1⁄2" notch about 1⁄2" deep from each stalk about 1" from the bottom. Transfer stalks to a plate and set aside.

3. For the mousseline sauce: Whisk mustard, vinegar, and egg yolk together in a medium bowl. Pour in oil in a steady stream, whisking constantly. After a thick mayonnaise forms, slowly add reserved asparagus water, 1 tbsp. at a time, to thin it out. Finished sauce should be slightly thicker than heavy cream (you will need 6-8 tbsp. of the water in all). Fold whipped cream gently into mayonnaise until mixture is smooth. Season with salt and pepper to taste and set aside.

4. To assemble: Pipe a 3 1⁄2" × 7 1⁄2" frame of cocktail sauce onto each of 4 rectangular plates. Put 2 tbsp. mousseline sauce in middle of each rectangle and gently spread it out, using the back of a spoon and tipping plate from side to side to fill each rectangle completely. Brush asparagus with hazelnut oil, fill each notch with 1⁄2-1 tsp. of the caviar, and garnish with chervil leaves. Place 3 stalks of asparagus on each plate, staggering them as shown at left.