1. On a floured surface, roll out 2 puff pastry sheets (one 17.3 oz box) to 13 x 9 inches; cut each sheet into 4 pieces.
2. Slice an 8 oz block of sharp cheddar cheese lengthwise into 8 strips (51/2 x 1-inch pieces); place 1 strip on each puff pastry piece, along with a fully cooked apple chicken sausage (from two 12 oz packages).
3. Brush edges with beaten egg, wrap pastry around cheese and sausage, and pinch edges and ends to enclose. Brush pastry with egg and sprinkle with caraway seeds.
4. Refrigerate for 30 minutes. Slice each pastrywrapped sausage into 6 pieces; place on parchment-lined baking sheets. Bake at 400 degrees for 15 to 18 minutes or until golden brown. Serve with grainy mustard.