In advance of preparing the bread mix, I soak ¼ cup sunflower seeds and ¼ cup pumpkin seeds in filtered water with 1tsp sea salt for a few hours or overnight, then I strain them. I also feed the sourdough starter a few hours earlier (or the night before if I'm doing it in the morning) so that it's active and full of bubbles.
To prepare the dough, put a large mixing bowl on your kitchen scales and hit tare. Add all the gluten free flours (you can hit tare each time so you know how much of each to add), salt, guar gum, chia seeds, sunflower and pumpkin seeds. Mix together with a wooden spoon.
In a small bowl, add two eggs, olive oil, and apple cider vinegar. Whisk together with a fork.
Make a well in the flour mix, then pour the egg mix in. Add the sourdough starter, then add 1 cup of water and carefully mix everything together with a wooden spoon. Add the rest of the water gradually, making sure you scrape the bottom of the bowl with your spoon to ensure all the flour is mixed in. You want it to end up like a really thick batter, so add a wee bit more water if you need.
Cover the bowl and leave in the fridge for 12-24 hours so that it's risen a bit. In the winter when it's cooler, you can leave your covered dough out at room temperature overnight (approx. 8 hours). Transfer to your greased loaf dish and let it sit out for an hour or so before putting it into a cold oven. (I also put a dish with about a cup of boiling water in the oven because I think the steam improves the crust?!) Turn the oven on to 180°C and bake for 1 hour 15 mins.
When the bread is cooked, transfer it onto a wire rack and leave it to cool completely before slicing.