*FOR THE PIZZA CRUST*
Dissolve the yeast in warm water with sugar. After 5 minutes, stir in the salt, johnnycake meal, wheat flour and oil. Gradually add the white flour, stirring with a wooden spoon until a stiff dough has formed.
Empty the dough onto a floured board, and knead it for several minutes, adding enough flour to keep the dough from sticking. When the dough is smooth and shiny, transfer it to a bowl that has been brushed with olive oil. To prevent a skin from forming, brush the top of the dough with additional olive oil, cover the bowl with plastic wrap, and let the dough rise in a warm place, away from drafts until double in bulk, 1 1/2 to 2= hours.
Punch down the dough and knead once more. Let the dough rise again for about 40 minutes. Punch down the dough. If the dough is sticky, knead in a bit more flour. Dough should be very soft however.
*TO ASSEMBLE AND GRILL THE PIZZA*
Prepare a charcoal fire, setting the grill rack 3-4 inches above the coals.
On a large oiled inverted cookie sheet, spread and flatten the pizza dough with your hands into a 10-12 inch free form circle, 1/8 inch thick, do not make a lip. You may achieve a rectangle rather than a circle; the shape is unimportant; do take care to maintain even thickness.
When the fire is medium hot, use your fingertips to gently lift the dough by the two corners closest to you, and drape it onto the grill. Catch the loose edge on the grill first and guide the remaining dough into place over the fire. Within a minute the dough will puff slightly, the underside will stiffen, and grill marks will appear.
Using tongs, immediately flip the crust over, onto the coolest part of the grill. Quickly brush the grilled surface with olive oil. Scatter the garlic and cheeses over the dough and spoon dollops of tomato over the cheese. Do not cover the entire surface of the pizza. Finally, drizzle the pizza with 1/2 tablespoon olive oil.
Slide the pizza back toward the hot coals, but not directly over them. Using tongs, rotate the pizza frequently so that different sections receive high heat; check the underside often to see that it is not burning. The pizza is done when the top is bubbly and the cheese melted, about 6-8 minutes. Serve at once topped with the basil leaves and additional olive oil if desired.
NOTE: There are several traps and difficulties that with experience you will overcome. To start, be careful not to stretch the dough so thinly that holes appear. Don't despair however if small holes do appear. Though you cannot repair them, you can work around them. To avoid flare-ups, do not drizzle any of the oil into the holes.
When you are lifting the dough off the cookie sheet, it will invariably stretch; do not try to compensate for this by moving your hands apart. Work as close to the grill as possible so the dough is without support for a minimum amount of time. If after 8 minutes the cheese has not melted and the topping is not bubbling, either you have been too cautious in your approach to the coals, or you have used too much cheese and topping ingredients. A longer time on the grill will only dry out the pizza and toughen it. The ideal crust should be both chewy and crisp. Do not be timid about the preparation of this pizza. From start to finish, the bold act will reward you with a first rate pizza.