Step #6 Reduce heat to 350° F, continue baking till knife inserted off-center comes out almost clean, about 20 mins (cover edges with foil wrap if necessary).
Step #7 Beat egg whites with vanilla & cream of tartar till soft peaks form.
Step #8 Gradually add granulated sugar, beating till stiff peaks form.
Step #9 Spread over hot filling, sealing to the edge.
Step #10 Bake at 350° F till meringue is golden brown, 12 to 15 mins.