Step 1

For the dough: Whisk together the warm water, yeast and sugar in a bowl. Set aside until the yeast activates and becomes foamy, about 10 minutes.

Step 2

Whisk the flour and salt in a large bowl. Make a well in the center. Pour the foamy yeast mixture and the olive oil into the well. Using a fork, gradually incorporate the flour into the liquid mixture. Turn the dough onto a lightly floured surface and knead until very smooth, about 5 minutes.

Step 3

Put the dough in a lightly oiled bowl and cover with plastic wrap. Place in a warm area until the dough doubles in size, about 2 hours.

Step 4

For the topping: In the meantime, mostly drain the clams, retaining about 2 tablespoons liquid. Mix together the chopped clams and juice, olive oil, oregano and garlic in a bowl. Keep refrigerated until ready to use.

Step 5

Preheat the oven to 500 degrees F and adjust the rack to the lowest level. Put a pizza stone or turned-over baking sheet on the rack.

Step 6

When the dough has doubled in size, turn onto a lightly floured surface and stretch into a very thin rectangle, about 12 by 14 inches. Dust a pizza paddle or turned-over baking sheet with the cornmeal and place the dough on top; make sure it slides back and forth easily. If using, sprinkle the mozzarella all over the dough. Top evenly with the clam mixture and the Parmesan. Season with salt.

Step 7

Carefully slide the dough onto the hot pizza stone. Cook until nicely golden brown on top and bottom, 8 to 10 minutes. Sprinkle with the parsley and crushed red pepper. Drizzle with more olive oil if desired.