Potato Starch (Best Option)
1:1 (1 tablespoon potato starch per 1 tablespoon cornstarch)Potato starch is a highly effective thickener with a neutral taste and excellent clarity, making it ideal for thickening the meat and vegetable filling in Shepherd's Pie. It gelatinizes at a similar temperature to cornstarch, providing a smooth and cohesive texture.
When using potato starch, add it towards the end of cooking and avoid prolonged high heat to prevent breakdown. It thickens quickly and should be mixed with cold water before incorporation to avoid clumping.
Compared to cornstarch, potato starch yields a slightly more elastic and glossy filling, enhancing the mouthfeel without compromising the traditional flavor profile.