For the marinade, mix lemon juice, 1 teaspoon pepper, sugar and oregano. Fold in 6 tablespoons of oil. Wash all the meat, dab dry and cut into cubes of about 2 cm.
For the kebabs, place the meat separately on skewers and place them close together on a fat pan. Brush everything with the marinade, cover and leave to stand in a cool place for about 1 hour. Turn once after approx. 30 minutes.
Heat 4 tablespoons of oil in a very large frying pan. Brown the skewers in it in portions all around. Season with salt and pepper. Take them out and put them on the fat pan. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 15 minutes. Remove the skewers and arrange with the braised vegetables.
For barbecue fans: Grill the skewers on the preheated grill at direct heat for 6-10 minutes while turning, depending on the type of meat.