As an homage to her French roots, Countess Florence Daniel Marzotto serves a trio of vegetable purees alongside roast squab: a creamy mash of fall chestnuts, a nutty combination of celery root and turnips, and a smooth blend of carrots cooked in the Vichy style (with minerally sparkling water to brighten their flavor). More Carrot Recipes
In a large saucepan, cover the carrots with the sparkling water and bring to a boil over moderately high heat. Stir in 3 tablespoons of the butter and 2 teaspoons of salt. Reduce the heat to moderate and simmer until the carrots are tender when pierced with a knife and the cooking liquid is reduced to 1/4 cup, about 25 minutes.
Transfer the carrots and their cooking liquid to a food processor and let cool for 10 minutes. Add the remaining 1 tablespoon of butter and process until smooth. Add the chopped cilantro and pulse until just incorporated. Season the carrot puree with salt and pepper, transfer to a bowl and serve.
The carrot puree can be refrigerated overnight. Reheat gently before serving.