Combine the bread, rice and soy flours in a large bowl and set aside.
In a stand mixer fitted with a dough hook, add the cold water and the yeast. Mix well.
Slowly add the flour mixture and mix just until combined.
Add the salt, olive oil and mix on medium speed for about 8 minutes until the dough is smooth. The dough will seem very liquidy, which is normal in high hydration doughs like this.
Let rise at room temperature for two hours, performing a series of four folds every 30 minutes by lifting up one corner of the dough with a wet hand, pulling it up and bringing it back down on top of the dough on the opposite side. Turn the bowl a quarter of a turn and repeat 3 more times until all the dough has been folded upon itself. Keep covered with plastic wrap.
Transfer to a lightly greased bowl, cover with plastic wrap and let rise in the refrigerator for at least 24 hours and up to 48 hours.
About 2-3 hours before you want to bake your pinsa, turn the dough out onto a very well-floured surface. Divide it into 4 equal pieces with either a floured knife or a dough scraper/cutter.
One at a time, fold the corners into the center to form a nice, uniform ball. Flip over so the seam side is down, being careful not to flatten. Repeat with the remaining pinsa dough balls.
Generously flour a baking sheet and gently place the pinsa dough balls on it, being sure they have space to grow in size (proof). Sprinkle well with flour and cover the baking sheet with plastic wrap or a kitchen towel. Allow the pinsa dough to rise at room temperature for 1-3 hours or until doubled.
About an hour before baking, heat the oven to about 500°F/260°C
Gently place one dough ball on a well floured surface and working from the center outward, shape the dough into an oval by pressing your fingers into the dough and gently stretching or pushing it outwords.
Carefully move the pinsa dough to a parchment lined baking sheet and top with your toppings. Remember that ingredients such as prosciutto crudo and fresh mozzarella di bufala shouldn’t be added until after the pinsa has been baked.
If you are making pinsa bianca or plain, oiled pinsa, generously drizzle with olive oil and salt before baking.
Bake for 10-15 minutes until the crust is golden and the pinsa pizza feels firm on the bottom.
Let cool slightly and finish topping with any additional ingredients, including a drizzle of olive oil. Serve immediately or at room temperature.