Activate the yeast. Warm the water on the stove or microwave between 105-115°F (if you go over, just let it cool until the temperature is in that range so you don't kill the yeast). Transfer to a wide medium bowl and mix in the honey or sugar. Slowly sprinkle the yeast over the warm water. Let sit for 5-10 minutes while the yeast activates and foams. If the yeast hasn't gotten foamy by 10 minutes, the yeast may not be fresh, so try again with a new package.

Mix dry ingredients. Meanwhile, combine the brown rice flour, sorghum flour, tapioca starch, potato starch, psyllium seed husk, salt, and baking powder in the bowl of a stand mixer with the paddle attachment or a large mixing bowl.

Add wet ingredients. When the yeast/water mixture is ready, add it to the flour along with 1 tablespoon of olive oil and mix on low to combine. Increase speed to high and mix for about a minute, until the dough is super smooth. (If using a mixing bowl, mix with a silicone spatula). The dough will be very wet and runny at first, but will thicken up slightly as the psyllium soaks up the water after a few minutes.

Let rise in a glass bowl with olive oil. Put ¼ cup olive oil in a medium glass bowl and dump the dough into the bowl. Cover with plastic wrap and let rise in a warm place for 1.5-2 hours, until doubled in size. (I use the "proof" setting on my oven). If making in advance, you can skip this 2-hour rise, and put it straight into the fridge for 8-36 hours. When you're ready, remove it from the fridge and let come to room temperature for 30 minutes then move on to the next step.

Smooth into greased baking pan and rise again. Grease an 8x8 baking pan with softened butter or olive oil. Transfer the dough with oil into the prepared baking pan, cover with plastic wrap, and let rise in a warm place for 2 hours. (I use the "proof" setting on my oven).

Dimple the dough and top with olive oil and salt. Use your fingertips to add dimples to the dough. Drizzle with 2 tablespoons olive oil and top with flaky salt (and rosemary or other toppings, if using!).

Bake. Bake for 20 minutes at 425°F, then reduce heat to 350°F and bake for an additional 10-15 minutes, until the dough is nicely golden brown and springs back when gently poked in the center. 

Let cool for at least 20 minutes before slicing and serving. Letting it cool slightly will allow the fluffy air pockets to set and not become gummy. Note: Focaccia is best when served within a few hours of making it. After it sits for longer, it won't be as tender as when it's fresh, but pop it in the toaster to refresh that crispy outside and fluffy inside.