Heat the oil in a 20cm non-stick frying pan, add the courgette and cook for a few mins, stirring occasionally, until softened. Meanwhile, beat the harissa with the eggs and pour into the pan. Cook gently, stirring, to allow the uncooked egg to flow onto the base of the pan. When it is two-thirds cooked, leave it untouched for 2 mins to set. Slide onto a plate, then return to the pan, uncooked-side down, to finish cooking.
To serve, tip onto a board and spread with the houmous. Scatter with the pepper, olives and coriander. Cut into quarters and eat warm or cold.