Peel and finely chop the onion. Sort the spinach, wash and pat dry. Chop the dried tomatoes coarsely. Heat 1 tablespoon of oil in a large pan. Sauté the onion until transparent. Add the spinach and let it collapse while turning.
Season with pepper. Take out the spinach, mix with dried tomatoes and let it cool down.
In the meantime, wash the tomatoes, grate them dry and cut them into slices of about 2 cm thickness. Clean the garlic and cut into large pieces. Drain the olives. Wash sage and oregano and shake dry.
Wash the meat and dab dry. Cut a pocket in each fillet with a pointed knife, fill with spinach-tomato mixture.
Heat 3 tablespoons of oil in a large frying pan. Fry the meat for 5-6 minutes while turning it. Remove and place on a baking sheet with frying fat. Spread tomatoes, garlic, olives, oregano and about half of the sage leaves on the baking tray.
Sprinkle with salt and pepper. Sprinkle with 2 tablespoons of oil and bake in a preheated oven (electric cooker: 250 °C/ convection oven: 225 °C/ gas: see manufacturer) for approx. 10 minutes.
In the meantime, put the couscous in a bowl. Bring the stock to the boil, pour in and let it stand for about 5 minutes. Wash the lemon hot, grate dry and finely grate the peel. Halve the lemon and squeeze the juice.
Clean and wash spring onions, shake dry and cut into fine slanted rings. Loosen the couscous and mix with 1 tbsp. oil, lemon peel and spring onions. Season to taste with salt, pepper and lemon juice.
Remove tomatoes and meat from the oven and serve with the couscous.