Combine the flour, (fast action yeast if using), caraway and the salt. Add the sourdough starter, honey, oil and milk (if using yeast you will more than likely have to add 230g milk), mix until you have a smooth, fairly stiff dough, that's not too sticky. It should be firm, but if it seems too dry, add a little more water, a tablespoon at a time, and work until smooth. (If you're using fast action yeast you will definitely need to add more water)
Place in a plastic box with a lid and leave to rest overnight at room temperature (8 hours). Or leave at room temperature for 1 hour, then place in the fridge for up tp 24 hours. The mixture will only expand a little but should smell “yeasty” and slightly sour the next day.
Preheat the oven to 190°C Fan. Have a large baking tray ready in the oven.
Divide the dough into 24, (approximately 25g each). Shape each piece into a ball and flatten one at a time into a disc and place on a well-floured work surface (use more rye flour) and roll out as thin as you possibly can – around 1-2mm. Use a fork to prick all over the surface of each crispbread if you don't have a dimpled rolling pin. I like baking them with a hole in the middle but that is entirely optional. Continue until you've used all the dough.
Remove the tray from the oven and place the crispbreads on the hot tray and bake in batches. Bake for around 8-10 minutes until the discs are lightly browned. Watch carefully as there is not much difference between done and burnt! Once you have baked all the crispbreads turn the oven off and leave until it has cooled right down. Place the crispbreads on a baking tray, it doesn't matter if they're piled on top of one another and return to a preheated oven (110°C) and bake for a further 20 minutes, turn the oven off and leave the crispbreads to cool in the oven. Store in an airtight container and they’ll keep for several weeks.