Clean, wash and drain the carrots, cucumber and tomatoes. Cut the tomatoes into quarters and remove the seeds. Cut vegetables into small cubes. Peel and finely dice onion. Wash turkey breast, dab dry and cut into large cubes.
Put rice in boiling salted water and let it swell covered over low heat for about 20 minutes. Heat oil in a large pan and fry the meat in it until golden brown. Season with salt and pepper and remove. Sauté the onion in hot frying fat, add the carrots and deglaze with stock. Cover and cook for 3 minutes. Then add cucumber and tomatoes and simmer for another 3 minutes. Wash tarragon, dab dry and chop finely, except for a little bit for garnishing. Stir mascarpone and tarragon into the sauce, add meat again and simmer for about 1 minute. Stir in the sauce thickener, bring to the boil again briefly and season to taste with salt, pepper and lemon juice.
Then add cucumber and tomatoes and simmer for another 3 minutes. Wash tarragon, dab dry and chop finely, except for a little bit for garnishing. Stir mascarpone and tarragon into the sauce, add meat again and simmer for about 1 minute. Stir in the sauce thickener, bring to the boil again briefly and season to taste with salt, pepper and lemon juice. Put rice into greased ramekins or cups and turn out onto plates. Arrange vegetable turkey ragout around it and serve garnished with lemon and tarragon