Using a sharp knife, cut off ends of sausage casings. Squeeze out meat and discard casings. In a bowl, mix sausage, onion, thyme, sage and crushed red pepper. Set mixture aside.
Preheat oven to 400°F. Working on a lightly floured work surface, unroll 1 sheet of puff pastry so a long side is near you. Divide dough horizontally into 2 long rectangles. Repeat with remaining sheet of puff pastry.
Brush each rectangle with 2 tsp. mustard. Cut 6 vertical 1 1/2-inch strips from each rectangle and discard any excess pastry. Place 1 Tbsp. sausage mixture in center of each strip and, beginning at one end, roll dough around mixture, pressing seam to seal. Place each roll seam-side down on a rimmed baking sheet. Repeat with remaining strips and sausage.
Bake rolls until pastry is puffed and golden, 20 minutes. Let cool for 5 minutes before serving.
This recipe also appeared in the April 2007 issue.