In a covered saucepan over medium heat, cook gooseberries and water for 3-4 minutes or until tender. Stir in 3/4 cup sugar; set aside.
In another saucepan, combine 1/2 cup sugar and cornstarch. Gradually add milk until smooth; bring to a boil. Cook and stir over medium-high heat until thickened. Reduce heat; cook and stir 2 minutes longer. Remove from the heat.
In a bowl, beat egg yolks. Gradually whisk a small amount of hot filling into yolks; return all to the pan. Bring to a gentle boil; cook and stir for 2 minutes. Remove from the heat; stir in gooseberry mixture. Pour into pastry shell.
In a small bowl, beat egg whites until soft peaks form. Gradually add remaining sugar, beating on high until stiff peaks form. Spread evenly over hot filling, sealing meringue to crust. Bake at 350° for 10-15 minutes or until golden. Store leftovers in the refrigerator.