Prepare pasta according to package directions, drain.

While pasta is cooking, in heavy 3 quart saute pan over medium heat, brown sausage whole according to package directions, turning occasionally, about 20 minutes. Transfer to a paper towel to drain, cut crosswise into 1/4-inch thick slices. Return sausage to pan to brown on both sides, turning frequently, about 5 minutes. Transfer to a paper towel. Drain all but 1 tbsp. Drippings from pan and remove from heat.

To prepare fennel, trim stalks to within 1 inch of bulb. Finely chop feathery leaves to yield 1 cup, set aside and discard stalks. Cut off and discard bulb base. Cut bulb lengthwise into halves, then crosswise into 1/4-inch thick slices (about 3 cups).

To prepare fennel gramolata, in a small bowl, grate peel from both lemons, stir in chopped fennel leaves and garlic, set aside. Juice lemons in a separate bowl, stir in mustard and set aside.

Return pan to medium heat. Saute sliced fennel bulb until crisp/tender, about 3 minutes. Remove from heat. Stir in lemon juice mixture and sausage.

In a large serving bowl, combine pasta, fennel, sausage, and Parmesan; toss to mix well. Spoon fennel gremolata and almonds atop. Toss to incorporate just before serving.