Preheat the oven to 170°F. Line two or more cookie sheets with parchment paper. Fit two or more large pastry bags with decorator tips. Use a large closed star tip for fluted kiss-shapes or a plain decorating tip for standard kisses.
Place the egg whites in a spotlessly clean bowl and whip them with an electric mixer on medium speed until frothy. Add the cream of tartar. Start the mixer again and continue to beat the egg whites.
Once the egg whites form soft peaks increase the speed to high and gradually add the sugar, a little at a time. Beat the egg whites until they are very shiny and hold stiff peaks but are not dry or crumbly, about 6 minutes. To make sure the sugar has completely dissolved, rub a bit of the meringue between two fingers to see if any granules of sugar remain. If grains are present, continue to beat the meringue until the sugar has fully dissolved.
Divide the meringue and tint as desired using gel food color. Spoon the meringue into the prepared piping bags. Pipe meringues of all sizes onto the lined cookie sheets. Sprinkle some of the piped meringues with the white nonpareils before baking.
Bake for 90 minutes, turning them halfway through the cooking time to ensure even cooking. When the meringues are done they should be dry to the touch. You can remove them from the oven, or if time permits, turn off the oven and let them stand inside the oven until the oven cools completely. When cool, you should be able to lift the cookies easily from the parchment sheet.
Preheat oven to 350 degrees. Grease and flour an 8-inch cake pan.
Combine first six ingredients in bowl; add milk, oil and vanilla. Using an electric mixer, beat on low speed until combined, then beat on medium for 2 minutes. Add egg and beat two more minutes. Pour into buttered and floured 8-inch baking pan. Bake 25 to 30 minutes (or until toothpick inserted near center comes out clean). Cool on rack for 10 minutes. Remove from pan and cool thoroughly on rack.
Buttercream and Decors
In a stand mixer fitted with the whip attachment, mix together the butter and confectioners’ sugar. Begin mixing on low speed until the mixture is crumbly. Increase to high and beat for 3 minutes.
Add the vanilla extract and beat again for another minute until light and fluffy. If the buttercream is too stiff, add milk or heavy cream 1 tablespoon at a time until the mixture is of spreading consistency.
Assemble the cake. Use a 2 1/2 to 3 inch round cookie cutter to cut away a circle from the center of the cake, creating a wreath shape.
Cover the cake with the buttercream using an offset spatula. Immediately cover the cake with the meringues. Pile the meringues on top of each other and use buttercream to help stick them together so they don’t fall off of the cake when moved. You may have leftover meringues (serve them alongside the cake). Add the candy canes to the top of the cake. Use a little buttercream to hold them in place.
Keep the cake covered in plastic wrap or store in an air-tight cake keeper at room temperature. Do not refrigerate the cake. Moisture is the enemy of meringue cookies and they will become soft and weep if exposed to refrigeration.