In a bowl, combine the sugar, instant dry yeast, and 2/3 cup warm water (140 ml). Whisk together and let sit for 10 minutes, until a light foam forms on the surface.

In a separate bowl, add the psyllium husk powder and slowly pour in 1/4 cup water (60 ml), whisking vigorously. The mixture will quickly turn into a gel-like consistency.

In a large bowl, mix together the brown rice flour, cornstarch, oat flour, and salt. Whisk to combine evenly.

Add the yeast mixture and psyllium gel to the dry ingredients. Begin mixing by hand, then slowly drizzle in the olive oil. Knead for about 5-10 minutes until everything is well incorporated.

Shape the dough into a ball and place it back in the bowl (or in an airtight container) lightly greased with oil. Cover and let rise in a warm, draft-free place (such as a turned-off oven with the light on) for 3 hours.

Meanwhile, prepare the toppings. Season the tomato puree with 1/2 tablespoon olive oil, dried oregano, and a pinch of salt. Slice the roasted red bell pepper into strips and toss with the remaining olive oil, a pinch of salt, and garlic powder.

Let the dough rise again (in the same warm place as before) for 1 hour. It may not visibly rise much, but it will become very soft.

Spread the seasoned tomato puree over the dough, then add the roasted pepper strips and olives. Bake in a preheated oven at 430°F (220°C) on the second-lowest rack for 20-25 minutes, until the edges are crispy and golden.

Remove from the oven, sprinkle with chopped fresh parsley, and serve immediately!