We wondered if roasting the potatoes could concentrate and enhance potato flavor in dishes that usually call for boiled potatoes.
Our recipe for Potato Gnocchi (see related content) uses roasted potatoes in order to increase the gnocchi's earthy potato flavor. Leek and potato soup and mashed potatoes seemed like good bets for us to try carrying over this technique, as the moisture in the potatoes that would evaporate during roasting wouldn’t affect the recipes.
We gave roasting a shot, cooking whole russets in a 400-degree oven for 45 minutes before peeling them and proceeding with the recipes. As with the gnocchi, tasters agreed that roasting the potatoes first did deepen the potato flavor in all the dishes. This is due to the Maillard reaction, which produces malty, caramel notes starting at 250 degrees in roasted potatoes—a temperature that won’t be reached by boiling. Whether the additional flavor was an improvement wasn’t as clear-cut. Some tasters, who felt that mashed potatoes shouldn’t taste strongly of roasted flavors, found it an unwelcome change; others found it pleasing. But almost all tasters liked the deeper flavor that roasting lent to the potato soup, making roasting a technique that we’ll consider using in the future for soup.