You can substitute butter with margarine.

Makes 12 cookies
These cookies are inspired by Mallomars but taste much better. Freezing the Fluff-topped cookies before coating them with chocolate prevents the Fluff from losing its shape. We like Carr’s biscuits in this recipe for their round shape, crisp texture, and gentle sweetness. You can substitute 1 1/3 cups bittersweet chocolate chips for the bittersweet chocolate.

WHY THIS RECIPE WORKS:
Our Chocolate Fluff Cookies are the homemade alternative to Mallomars, a popular supermarket cookie a graham cracker base topped with marshmallow and covered with chocolate. We skipped the graham cracker in favor of Carr’s Whole Wheat Crackers, an English import found in the cookie aisle at most supermarkets. They are only lightly sweetened and have a crisp but sturdy texture. We froze the Marshmallow Fluff-topped cookies to enable easy covering with the chocolate. Adding a little vegetable oil to the melted chocolate helped it spread smoothly and kept it shiny.

http://www.americastestkitchenfeed.com/bake-it-better/2013/04/secrets-to-chocolate-fluff-cookies/

The Kids love these when they are made with M&Ms

Can be frozen.
24 servings. 1 bar = 220 calories, 10g fat, 40 mg cholesterol, 60mg sodium, 32g carbohydrate, 2g fiber, 24g sugars, 3g protein