This recipe for M&M cookie dough truffles comes from https://sixsistersstuff.com/recipe/m-cookie-dough-truffles/. The ingredients include: 2 1/2 cups all-purpose flour, 1 teaspoon salt, 1 cup (2 sticks) butter or margarine, room temperature, 3/4 cup granulated sugar, 3/4 cup packed brown sugar, 1 teaspoon vanilla, 1/3 cup skim milk, 1 tube of mini M&M’s (or two tubes if you like more M&M’s), 2 cups of Hershey's milk chocolate chips.
See the link for the cooking instructions. A slightly different recipe called M&M Truffles can be found at https://macnifique.com/?p=133. This recipe uses both Chocolate and Crispy M&M’s.