In the bowl of a stand mixer, combine the Caputo Fioreglut gluten-free flour, sorghum flour, millet flour, xantaan, tapioca, instant yeast, sugar and salt.
In a separate bowl mix together the warm water and psylliumfibers. After a minute a gel will form. Add the olive oil and yoghurt.
Pour the wet ingredients into the stand mixer bowl with the dry ingredients.
Using the stand mixer fitted with a paddle attachment, blend the ingredients on medium speed for 2 minutes until a smooth batter forms.
Put the dough in a bowl and let it rise for 1 hour covered with a cloth.
Grease a dark non-stick (8x10 or 9-inch square) pan generously with olive oil. Place the dough in the pan and pat it out to the edges, ensuring it covers the entire bottom of the pan.
Cover the pan with plastic wrap or a clean kitchen towel and let the dough rise in a warm place for 45 minutes , until puffy and almost doubled in size.
Preheat your oven to 220°C.
Drizzle a bit more olive oil over the dough. Then use your fingertips to randomly dimple the surface to gently press down the dough a bit.
Sprinkle with a big pinch of Maldon salt and push small springs of rosemary into the dimples you made earlier.
Bake for 20-25 minutes, on the bottom or lowest rack of your oven, until the crust is golden brown.
Remove the focaccia from the oven and let it cool slightly before slicing and serving.