Angel Food Cake Frosting
Melt chocolate chips and allow to cool. Whip cream until stiff peaks form. Fold in melted chocolate.
French Meringue Buttercream
In mixer, whip egg whites until foamy. Increase speed of mixer and slowly start adding sugar until all incorporated. Then increase speed even more and whip until the mixture is shiny and stiff (meringue).
With mixer at medium, start adding the butter a bit at a time. Once all butter added, turn mixer on high and mix for 5-15 minutes. If still lumpy and failing to form buttercream, warm mixture up a little bit and continue mixing. Optionally add cocoa powder. When buttercream is done, the mixture will be homogeneous and without lumps.
Place egg whites and sugar into the bowl of a stand mixer, whisk until combined.
Place bowl over a pot with 1-2" of simmering water and stir constantly with a whisk until the mixture is hot and no longer grainy to the touch or reads 160F on a candy thermometer (~3 mins).
Place bowl on your stand mixer and whip on med-high until the meringue is stiff and cooled (the bowl is no longer warm to the touch, 5-10mins). Switch to paddle attachment. Slowly add cubed butter and mix until smooth. Add cooled melted chocolate and espresso powder. Mix until combined. Slowly stream in Kahlua and whip until smooth.
Milk Chocolate Buttercream Frosting
Melt the chocolate: combine cream and chocolate. Stir, and microwave 30 seconds. Repeat until well mixed. Set aside and allow to cool.
Cream the butter and sugar until light and fluffy. Add the vanilla and (cooled) chocolate with the mixer on slow speed until constituted. Beat frosting on medium setting for 3 additional minutes.
Dark Chocolate Ganache
Heat the heavy cream in a microwave on high until if just begins to simmer - be careful not to allow cream to boil.
Combine both ingredients to a mixing bowl. Process by pulsing several times until chocolate mixture is smooth. Use as is for glazing, or allow to come to room temperature and then whisk to make a lighter frosting.