The flavors of spring punctuate each roll.
- In large pot, combine 6 quarts water, 1 teaspoon salt and olive oil. Bring to a boil and add the lasagna noodles. Cook to al dente; drain noodles. Cool under running water.
Handle the noodles gently from this point forward. Lay noodles on a plastic-lined tray; lightly oil the plastic.
To blanch asparagus, bring 3 quarts water to boil in a large pot. Add 1 teaspoon kosher salt. Add the asparagus and cook for 3 minutes. Immediately drain the asparagus and chill under cold running water or place in an ice water bath. When asparagus is chilled, remove and place on paper toweling to dry.
To prepare leek strings, wash leeks, trim and cut lengthwise into pieces about the size of a shoelace. Place leek strings in a pan of boiling salted water for approximately 3 minutes. Plunge leek strings immediately into ice water bath to stop cooking process. Drain.
In small bowl, combine mascarpone, cream, dill, garlic, lemon zest, red onion, capers, Dijon mustard, 1 teaspoon kosher salt and pepper. Mix well and refrigerate 1 hour before using.
To assemble spring rolls, lay out noodles, spread mascarpone mixture down the middle of each and divide the salmon among the noodles. Add three asparagus spears to each spring roll; carefully roll the noodles around filling and tie each with a blanched leek string.