Pastry: In bowl, whisk together flour, sugar, baking powder and salt. With pastry blender or 2 knives, cut in butter until in coarse crumbs.
In small bowl, beat together egg, egg yolk and lemon rind. Using fork, stir into crumbs to form ragged dough. Press together. Divide in half.
Press slightly more than half of the pastry over bottom and up side of 9-inch (23 cm) tart pan with removable bottom; spread with jam. Wrap remaining pastry in plastic wrap; refrigerate pastry and tart shell until firm, about 30 minutes.
On lightly floured surface and using hands, roll remaining pastry into 14 ropes, each 10 inches (25 cm) long.
Place 1 rope across centre of tart. Add 3 more ropes, equally spaced, on each side of centre. Press overhang to trim and seal.
Repeat with remaining ropes, positioning at 45-degree angle over first layer to make diagonal lattice.
Bake in centre of 350 degrees F (180 degrees C) oven until pastry is golden, about 45 minutes. Let cool on rack. (Make-ahead: Cover with foil; set aside for up to 24 hours.)