In a pyrex jug, mix together the yeast, caster sugar and warm water and leave for 15 minutes to activate.
In a separate bowl, weigh out the flour, salt and xanthan gum.
Stir the yeast mixture into the dry ingredients and stir well. Add the garlic-infused oil and olive oil and mix.
Grease and line a tin with baking paper and transfer the bread mixture. Cover with cling film and a tea towel, then leave to prove in a warm place for one hour.
Preheat the oven to 220 degrees Celsius or gas mark 8.
Dip your finger into olive oil then press gently to create dimples in the dough. Repeat until you have your desired pattern. Drizzle with oil and add rosemary sprigs.
Bake for 25 minutes, leave to cool, then serve.