Put molasses in heatproof bowl. Sprinkle baking soda over top. Add boiling water; whisk with fork.

Blend flour, ginger, cinnamon, cloves, nutmeg, pepper and salt in large bowl. Cream margarine and brown sugar in another bowl. Add molasses mixture; beat until soft dough forms. Divide in half, wrap each in plastic wrap and chill 1 hour.

Put 1 dough ball between 2 sheets wax paper. Roll into 8 1/2 x 12 1/2-inch shape; remove top wax paper. Using sharp knife, trim dough edges; cut dough into 12 2x4-inch rectangles. Prick with fork. Transfer on wax paper to cookie sheet; chill 30 minutes. Repeat with remaining dough.

Preheat oven to 325 degrees F. Grease 2 cookie sheets. Transfer rectangles from wax paper to cookie sheets.

Bake 8 to 10 minutes, or until set but still soft to the touch. Transfer to wire rack, and cool completely.

Meanwhile, scoop sorbet and ice cream into large bowl; blend with wooden spoon. Freeze 20 minutes or longer, or until mixture is firm.

When completely cool, spread 1/2 cup frozen lemon filling onto bottom of one cookie. Pat filling down with spatula. Place second cookie on top (pricked side up), and gently press down. Scrape away any filling that spreads past edges, and use it to fill in corners. Smooth edges. Repeat with remaining cookies. Wrap sandwiches in plastic wrap, and freeze until firm, about 30 minutes.