Cook the pasta in salted water according to the instructions on the packet. Preheat the oven to 180 ° C. Meanwhile, wash the vegetables and cut them into small cubes. Finely chop the garlic.
Heat some olive oil in a pan and fry the onion, garlic and vegetables in it. After about 5 minutes add the rosemary sprigs. Briefly continue frying and add the tomatoes. Season everything with salt, pepper and a little chilli.
Melt the butter in a small saucepan, dust with flour and deglaze with milk. Simmer for about 5 minutes, stirring constantly, season with salt and pepper and stir in the grated cheese. Mix the vegetables with the pasta and place in a gratin dish.
Crumble the sauce on top and the feta cheese. Baked in the oven for about 25 minutes. Tomato salad, green salad or fresh baguette tastes good with it.