In a large bowl, cream together the butter and 3/4 cup sugar until smooth. Mix in egg. combine the flour, cream of tartar, baking soda and salt; stir into the creamed mixture until just blended. Press dough into an ungreased pizza pan.
Bake in preheated oven for 8 to 10 minutes, or until lightly browned. Cool.
In a large bowl, beat cream cheese with 1/2 cup sugar and vanilla until light. Spread on cooled crust.
Arrange desired fruit on top of filling, and chill.