Grilled Pizzas

1 1/2 cups warm (110 degrees F) water
1 package dry yeast
2 teaspoons salt
1/2 teaspoon garlic powder
1/4 cup olive oil
4 cups unbleached all-purpose flour

In a large bowl, whisk together water and yeast; let stand for 5 minutes. Whisk in salt, garlic powder and olive oil. Stir in about 3 1/2 cups of the flour, or until a soft dough forms. Sprinkle the work surface with the remaining flour, turn out the dough, and knead until smooth, about 5 minutes. Lightly oil a large bowl. Put in the dough, turn it too coat it with oil, and cover with a clean towel. Let the dough rise until it is puffy and light