Directions

1. 1. Put the stock in a large, deep saucepan or casserole and turn the heat to medium-high. When it is just about boiling, turn the heat down to medium so that it bubbles but not too vigorously. Stir in the rice, carrot, and celery and cook, stirring occasionally, until the vegetables are all tender, about 20 minutes. Season with salt and pepper and add the tomato if you're using it; turn the heat under the soup to low.
2. 2. Use a whisk to beat the eggs in a bowl with the lemon zest and juice; still beating, add about 1/2 cup of the hot stock. Gradually add about another cup of the stock, beating all the while. Pour this mixture back into the soup and reheat, but under no circumstances allow the mixture to boil or the eggs will scramble.
3. 3. Taste and add salt, pepper, or lemon juice as necessary. Garnish with the dill and serve.