Put the flour and salt in a large bowl and make a well in the middle. Tip in the yeast, sugar and 300ml lukewarm water and mix together with a wooden spoon.
Knead the dough on a lightly floured surface for 5 minutes, until smooth and elastic. Transfer the dough to a lightly oiled bowl, cover with clingfilm and leave for 1 hour, until doubled in size.
Meanwhile, heat the olive oil in a large pan over a medium-low heat and fry the onion for 8-10 minutes until softened. Add one of the sliced garlic cloves and rosemary and fry for a further 1 minute. Set aside. Preheat the oven to 220°C/fan 200°C/gas mark 7.
When the dough has risen, knock it back, then transfer to a baking sheet and spread it out with your hands to make a rough 34cm diameter circle. Using your fingers, make little dimples all over the dough, then spread the onion mixture over the top. Drizzle with a little olive oil and bake for 15-20 minutes, until golden on top and soft in the middle.
Meanwhile, remove the sleeve and wrapper from the camembert fondue and replace it in its ceramic baking dish. Cut a cross in the top of the rind and poke in the second clove of sliced garlic. Scatter over the thyme leaves and drizzle with the honey.
When the bread is baked, remove from the oven and cover loosely with foil to keep warm. Reduce the oven temperature to 190ºC/fan 170ºC/gas mark 5. Bake the camembert in its dish until oozing in the middle, then serve on a board with the warm bread to tear and dip in.