Preheat the oven to 220C/200C Fan/Gas 7. Mix the flour, baking powder, yeast and salt together, making sure you crumble up the salt well.
In a separate bowl or jug, mix the honey, water and butter together. Add the wet ingredients to the dry ingredients and mix until it comes together as a dough. Turn out onto a work surface and knead for a couple of minutes until smooth. Cover with cling film or a damp cloth and leave to stand for half an hour.
Roll the dough out as thinly as you can and use a cookie cutter to make small rounds, or cut into wide strips – it depends how rustic you want these to look. Arrange over a couple of baking trays and prick thoroughly all over with a fork. Brush with olive oil and sprinkle over the onion seeds and thyme leaves.
Bake in the oven for 8-10 minutes, or until crisp and burnished. Transfer to a cooling rack. They will continue to crisp once out of the oven.