Begin by combining the marshmallow cream, a portion of the confectioners' sugar, the melted and cooled unsweetened chocolate, butter flavored shortening, and half of the half-and-half in a large mixing bowl. Use a spatula to ensure all ingredients are well incorporated before turning on your electric mixer. Beat on medium speed for about 2-3 minutes, until the mixture is smooth and well-blended, with no lumps.

Once your initial mixture is smooth, gradually add the remaining confectioners' sugar and half-and-half, alternating between the two. This method helps prevent clumping and ensures even consistency. Continue mixing on medium speed for another 3-5 minutes, or until the frosting reaches your desired sweetness and texture. Look for a creamy, fluffy consistency that holds its shape but is still spreadable for your cakes and cupcakes.

After achieving the perfect consistency, take a moment to taste the frosting. If you wish, adjust the sweetness by adding more confectioners' sugar, or add a touch more half-and-half if it feels too thick. Once satisfied, use a spatula to transfer your luscious Chocolate Marshmallow Frosting into a piping bag or directly onto your cakes and cupcakes. Decorate as desired, and enjoy the delightful outcomes of your baking adventure!