Place quinoa in a fine sieve, rinse thoroughly and cook in 600 ml salted water according to the instructions on the packet. In the meantime, wash the tomatoes, cut off a lid on the stem side and hollow out the tomatoes.
Wash and clean spring onions and cut into fine rings. Drain the quinoa and rinse with cold water. Mix quinoa, about half of the spring onions and about half of the cottage cheese, season with salt and pepper.
Fill the tomatoes with the quinoa mixture and place them with the lids on a baking tray. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for about 12 minutes. Remove the tomatoes from the oven, spread the remaining cottage cheese and spring onion rings on top and serve.