Preheat oven to 325°.

Line two 24 count mini muffin pans with paper liners. (The brownies can be difficult to remove from the pan without liners, but you can use nonstick baking spray with flour.)

In a large mixing bowl, whisk together water, oil, and egg until well combined. Add brownie mix and stir until well blended. Scoop 1 tablespoon brownie batter into each of the paper-lined muffin cups.

Bake brownies 14 minutes until the brownies are firm to the touch.

Put 4 miniature marshmallows in the center of each brownie. Return to the oven, and bake until marshmallows begin to puff, 1 to 2 minutes. Cool in pan 5 minutes. Transfer brownies to a wire rack to cool before frosting.

Prepare Chocolate Glaze: Put the chocolate in a small glass bowl and set aside. In a small microwave-safe bowl, combine heavy cream and corn syrup; microwave heavy cream just until it starts to boil, about 30 seconds. Pour over the chocolate; set aside for 3 minutes. Whisk until chocolate is melted and smooth. If necessary, microwave an additional 10 seconds at 50% power.

Drizzle a spoonful of the glaze on top of the marshmallow. Top with M&M Baking Bits or other colorful candies.