Prepare and bake cupcakes as per recipe instructions. Allow to cool.
FOR THE MARSHMALLOW MERINGUE:
Make sure your bowl and utensils (whip attachment) are very clean! You can take a paper towel with a little bit of white vinegar or lemon juice and wipe both the bowl and whip with this to make sure they are truly clean and there is no greasy residue (grease will inhibit the egg whites from reaching stiff peaks). Combine the egg whites and sugar in the bowl of a stand mixer over a double boiler (a saucepan with about one inch of simmering water). Don't let the bottom of the bowl touch the water.
Whisk constantly until the sugar has dissolved and the mixture is hot to the touch (about 160 on a thermometer) or when you rub a bit of the mixture between two fingers and feel no sugar crystals. This will take about 5-7 minutes.
Remove the bowl and place it on the stand mixer. Using the whisk attachment, whip the mixture, gradually increasing the speed to high, until medium peaks (mixture will have increased in volume, but is not yet stiff or shiny).
Add cream of tartar and vanilla extract (and any food coloring, if using--NOT oil-based) and continue to whip at high speed until stiff peaks (the mixture will hold a peak straight up) and the meringue is very shiny.
Fill a pastry bag fitted with a large round tip (tip 1A) with the meringue. Pipe the meringue onto the cupcakes in a very high swirl.
Refrigerate cupcakes for about 30 minutes.
FOR THE CHOCOLATE DIP:
While the cupcakes are chilling, melt the chocolate and canola oil in a large heatproof bowl set over a pan of simmering water (the same double boiler used for the meringue). When completely melted and smooth, pour into a deep container to allow enough room for cupcakes to be dipped straight up and down.
Allow the chocolate dip to cool slightly before dipping the cupcakes.
TO DIP THE CUPCAKES:
Remove the cupcakes from the fridge and, holding the cupcake near the top at the wrapper, turn it upside down and dip straight down into the chocolate to completely cover the cake to the wrapper. Pull it straight out and allow excess chocolate to fall back into container before turning right side up. Don't tap on the side of the container as you may risk the meringue falling in.
Place the dipped cupcake onto a baking sheet and continue until all the cupcakes are dipped.
Put the cupcakes back in the refrigerator to chill for about 30 minutes while preparing the fondant.
TO MAKE THE FONDANT BRIMS:
Roll out each color of fondant into a circle about ⅛ inch thick. Cut two circles, one larger than the other, and use the outside "ring" as the brim. Using a sharp knife, cut a slit in each ring.
Remove the cupcakes from the refrigerator and wrap the fondant "brims" around each cupcake, pressing together the cut ends to seal. Gently press the brims against the chocolate to stick it to the cupcake (this should stick very easily when the cupcakes are just out of the fridge and condensation is forming). Otherwise, you may need to brush the bottom of the chocolate gently with a little water.
Using your thumb and forefinger, gently squeeze the brim around the cupcake at the edges to thin it out and create movement.