Preheat the oven to 450°F. Put a pizza stone or an inverted baking sheet on the lowest rack.
In a large mixing bowl, combine flours, baking powder and salt. Add olive oil and water to make a shaggy, sticky dough.
Turn it out onto a lightly floured surface and knead into a smooth and elastic ball, about 2~3 minutes.
Divide the dough in half and shape each half into a flat disk. Wrap each disk in plastic wrap and let rest in a warm place for 15 minutes.
Take 2 large sheets of parchment and spray them with cooking spray. Place one dough disc between the parchment, oiled-sides in; and roll into a 12~14-inch round about 1/8 inch thick.
Remove the top parchment and transfer the dough with the bottom parchment onto the pizza peel.
Spread half of the tomato sauce on the crust and top with the other toppings. Slide the pizza onto the hot stone or baking sheet.
Bake until crust is crisp and golden brown and the cheese is bubbling, about 10~12 minutes.
Transfer to a cutting board and sprinkle with basil leaves. Cool 1~2 minutes before slicing. Repeat with the second pizza.