Combine ricotta, ground almonds, sugar, and lemon rind in a blender, and pulse to just mix. Add vanilla, then eggs, one at a time, pulsing briefly after each addition. Pour mixture into pastry. Cut tin foil to just cover filling, and place over pie. Bake for 5 minutes at 425 degrees F, then another 30 minutes at 325 degrees F. Pull foil off for last 5 minutes and cook until center is firm. Cool before cutting.