Adjust rack to lower third of oven; preheat oven to 325 degrees F. Sift the flour, cinnamon, salt and baking powder onto a strip of waxed paper. Combine the butter and sugar in a large bowl; beat until smooth. Add the egg and beat until well blended. Stir in flour mixture, nuts and lemon zest just until thoroughly blended. Divide dough in half. Using floured fingertips, pat half of the dough evenly into an ungreased 9-inch square baking pan. Spread jam evenly over the dough, stopping 1/2-inch from edges. Set aside. Roll the remaining dough between 2 pieces of waxed paper to a 9-inch square. Place on a baking sheet and refrigerate until firm. Cut dough into 14 strips, each 1/2 inch wide. Evenly space 7 of the strips over the torte in one direction. Place remaining strips at right angles to the first strips, creating a lattice pattern. This technique is not actually weaving, but the results are just as impressive. Bake for 45 minutes, or until light golden. Cool completely before cutting into 2-inch squares. Yields 16 squares. PER SQUARE: 225 calories, 3 g protein, 23 g carbohydrate, 14 g fat (5 g saturated), 33 mg cholesterol 44 mg sodium, 1 g fiber. Flo Braker writing in the San Francisco Chronicle, 9/29/93. Posted by Stephen Ceideburg