Dough: Dissolve sugar and yeast in water. Set aside.
Mix flour and salt in a large 4 to 5-quart mixing bowl. Make a well in the
flour; add the yeast mixture and vegetable oil. Mix and knead thoroughly
until a rough mass of dough is formed that cleans the sides of the bowl. Turn
the dough out onto a floured work surface; knead for 5-6 minutes until the
dough is smooth and soft. Dust with flour if the dough sticks to your hands.
Dust the dough lightly with flour; place in a lightly floured mixing bowl.
Cover the bowl with plastic wrap and a kitchen towel. Set it in a warm place
to rise for 1 - 1 1/2 hours, until doubled in bulk.
Punch down the dough; turn it out onto a work surface and knead for about 1
minute. Divide the dough into pieces -- 1 slightly larger. Roll out the
larger piece (this will be the bottom layer of dough) until it is about 3
inches larger than the pan and 1/8 inch thick. Oil the bottom and sides of
the pan. Place the dough in the pan; push it into the bottom and sides. The
dough should overlap the pan by about 1 inch. Trim off the excess overlap
with a knife. Set the pan aside. Roll out the second piece of dough until it
is about the same size as the pan.
Sauce: Drain off all the liquid from each can and crush the tomatoes with your hands and then add the remaining ingredients (do not cook).
Stuffing: Wash the spinach thoroughly and dry it completely. Remove the stems. Finely chop the leaves (food processor works nicely). In a 2- to 3-quart mixing bowl, combine the spinach and mozzarella.
To Assemble and Bake: Preheat the oven to 475F. Put the spinach and cheese
mixture into the pan. Lay the second piece of dough over the spinach-cheese
mixture. Crimp the 2 edges of dough together with your fingers to form a
thick border. Press down on the filling with your hand. Cut a 1-inch slit in
the center of the top crust to allow steam to escape.
Spread the tomato mixture evenly over the top crust.
Bake the pizza in the preheated oven, on the lowest rack, for 10 minutes.
Move the pizza to an oven rack 2 slots above the lower rack and bake an
additional 25-30 minutes, until the crust is lightly browned.