Peel and finely chop the onion. Heat the oil in a pot. Brown onion and Ebly in it. Add 200 ml water and bring to the boil. Season with salt and swell for about 10 minutes. Drain Ebly if necessary.
Drain the tomatoes and cut them into cubes. Clean and wash the arugula and put aside about a quarter. Cut the rest into strips. Grate parmesan. Mix Ebly, tomatoes, rocket strips, olives and half of the parmesan.
Season to taste with salt and pepper.
Wash the zucchini, halve lengthwise and remove seeds. Fill with the Ebly mixture and place on the fat pan of the oven.
Dissolve the stock in approx. 1/2 l hot water and pour into the courgettes. Bake in the preheated oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3) for approx. 20 minutes. About 5 minutes before the end of the baking time, sprinkle remaining parmesan over the courgettes.
Arrange the zucchini, garnish with the rest of the arugula.