Wash and dry the tuna steaks, then brush them thinly with olive oil and season with salt, pepper, rosemary and thyme. Then roll in flour, brush thinly with the egg and sprinkle generously with sesame seeds.
Heat some olive oil in a pan and fry the tuna on both sides for 1 - 1.5 minutes over a higher heat. Then finish frying for approx. 2 - 3 minutes on each side at a low temperature. The breading should be light brown, the tuna should still be slightly pink on the inside.