Punch down the risen dough, cut into two equal portions and roll each portion out into a large rectangle. Sprinkle with cheddar cheese and thyme/rosemary, if using. Roll the rectangle up from the short edge creating a tight 'jelly roll'. Repeat with the second portion of dough.
Using a very sharp knife, cut eat jelly roll of dough in half lengthwise. Pinch the ends of each halved roll together and braid them, one over the other, finishing the other end by pinching that dough together. Lightly grease two loaf pans, or line them with parchment paper. Gently place one dough braid in each loaf pan. Cover with a tea towel and let the dough rise a second time for approximately an hour.
Preheat oven to 350 degrees. Bake for 50 minutes, rotating the pans halfway through the baking time so they cook evenly. If the bread is browning too fast, move it to a lower rack in the oven and cover the top with a piece of aluminium foil. Let the loaves cool in the pan for 5 minutes before removing them from the pan.