Transfer dough to lightly floured surface and knead until smooth. Place in buttered bowl and allow to rest covered for 30 minutes. Divide dough into 2 or 4 equal parts. Roll each into a smooth tight ball. Place on cookie sheet, cover with damp towel and refrigerate. Remove dough from refrigerator 1 hour before baking and let come to room temperature. On lightly floured surface, flatten each ball of dough into a 6 inch circle for smaller pizza and 10 inches for the larger.