Step 1: Grease a 9×13 inch baking dish (or two 8×8 inch dishes) with butter or cooking spray. Lightly grease a sheet of parchment paper or wax paper for pressing.
Step 2: In a large, heavy-bottomed pot, melt the unsalted butter over low to medium-low heat.
Step 3: Add the 10 ounces of mini marshmallows to the melted butter. Stir continuously until the marshmallows are completely melted and smooth. Remove from heat.
Step 4: Quickly add the crispy rice cereal to the marshmallow mixture. Fold gently with a rubber spatula until the cereal is evenly coated.
Step 5: Transfer the mixture into the prepared baking dish. Using the greased parchment paper or a lightly buttered spatula, gently press the mixture evenly into the pan. Do not press too firmly.
Step 6: Let the treats cool completely at room temperature (30-60 minutes). Once cooled, cut into rectangles or squares (approx. 3×4 inches).
Step 7: Dip the bottom of each large marshmallow (for the head) into a small amount of melted marshmallow mixture or royal icing. Place one sticky marshmallow onto the center of each Krispie treat rectangle. Allow to set.
Step 8: Prepare royal icing: tint small amounts black for eyes and mouth, and orange for the nose. Using a fine-tipped piping bag or a toothpick, draw two dots for eyes and a dotted smile on each large marshmallow head.
Step 9: Draw a small orange triangle in the center of the face for the carrot nose using orange icing.
Step 10: Gently press two mini pretzel sticks into the sides of the large marshmallow head for arms. Place 2-3 mini chocolate chips or small sprinkles down the Krispie treat base for buttons.
Step 11: Cut fruit leather or fondant into thin strips. Drape a strip around the base of each snowman’s head for a scarf.
Step 12: Optionally, dust lightly with powdered sugar or add festive sprinkles around the base. Allow all decorations to set completely before serving or storing.