BEAT shortening, peanut butter and sugar in large bowl at medium speed of electric mixer until well blended. Beat in egg, milk and vanilla.
COMBINE flour, baking soda and salt. Add gradually to creamed mixture at low speed. Beat until well blended.
CUT two pieces of wax paper to a size of 15 x 10 inches. Place dough on one sheet, top with second sheet, then roll dough to the edges. Mix jam with cornstarch until dissolved and smooth. Remove top piece of wax paper. Spread jam mixture on dough evenly to within 1/2-inch of edges.
LIFT up long side of wax paper. Loosen dough with spatula. Using the wax paper, roll up dough jelly-roll fashion. Seal seam. Wrap in the wax paper to freeze for 1 hour or wrap in plastic wrap to refrigerate overnight.
HEAT oven to 375 degrees F. Coat baking sheet lightly with no-stick cooking spray. Unwrap dough. Cut into 3/8-inch slices. Place 2-inches apart on prepared baking sheet. Return dough to freezer until all cookies are sliced.
BAKE 11 to 12 minutes or until set. Cool 1 minute on baking sheet before removing to cooling rack.
TIP By freezing the dough, a nice clean cut can be made when slicing to make cookies.