In a large bowl, combine the flour, sugar, baking powder and salt; cut in butter until crumbly. Combine eggs and vanilla; stir into crumb mixture until blended. Cover and refrigerate a fourth of the dough for at least 45 minutes.
Press remaining dough into an ungreased 15x10x1-in. baking pan. Spread 1/4 cup apricot preserves in a 1-3/4-in. strip over one long side of crust. Spread 1/4 cup of raspberry preserves in a 1-3/4-in. strip adjoining the apricot strip. Repeat twice.
Roll out reserved dough to 1/8-in. thickness. Cut into 1/2-in. strips; make a lattice top. Bake at 325° for 30-35 minutes or until lightly browned. Cool on wire rack. Cut into bars.