Preheat the oven to 350°F and prepare a cupcake tin by spraying with cooking spray and then lining with cupcake liners. 

Sift together the flour, baking soda, salt, cocoa powder, and cinnamon in a medium sized bowl. Set aside.

In a small bowl, combine the coffee, milk, and oil. Set aside. 

In the bowl of a stand mixer, cream together the butter and sugar on medium-high speed until light and fluffy. 

Add the vanilla extract and beat to combine. 

Add the eggs, one at a time, and beat until smooth.

Lower the mixer speed to the slowest setting and alternate between the wet and dry ingredients, beginning and ending with dry. (The additions should be as follows: dry, wet, dry, wet, dry).

Beat until just combined and smooth. Try not to overwork the batter.

Spoon the batter into the prepared cupcake tins and fill about 3/4 of the way full.

Once the tin is filled with batter, bang the tin on the counter to level out the batter.

Bake for 28-30 minutes, until the tops are puffed and a cake tester (or toothpick) comes out clean when inserted into the middle. You can also tell if they are done if you poke the top and the cupcake quickly springs back.

Cool the cupcakes on a cooling rack until completely cooled and they ready to be frosted.

In the bowl of a stand mixer, combine the egg whites and sugar. 

In a small pot, bring some water to a simmer. You will place the stand mixer bowl over the simmering water, so you don't want the bowl and the water to touch. 

Once the water is simmering, place the bowl with the eggs and sugar over the simmering water. 

Whisk vigorously until the mixture becomes opaque white and the sugar is completely dissolved - about 5-7 minutes. 

Move the bowl to the stand mixer.

With the whisk attachment, beat the egg mixture on the highest speed until completely cool - about 10 minutes. It should be glossy and thick - and almost look like melted marshmallows. 

While the egg mixture is beating, melt the chocolate in the microwave in 20 second intervals, stirring after each interval. Continue until the chocolate is completely melted and smooth. Set aside and let it cool.

Once the egg mixture is completely cool, add the butter. Add it one tbsp at a time, until the mixture is thick and creamy. Wait for each tbsp of butter to be incorporated before you add the next one. 

Once the butter is fully incorporated, turn off the stand mixer. Use a spatula to remove anything from the sides of the bowl and anything from the bottom that may not be fully incorporated.

Turn the mixer back onto the highest speed and beat for 1 minute to combine. 

Turn the mixer off again and add the chocolate, coffee, and salt. You don't want the mixer to be on for this because the melted chocolate will fling all over the place when it hits the whisk attachment. (Kind of like tie-dying with chocolate, which is cool in theory but not in practice).

Turn the mixer back onto the highest speed and beat until combined. 

Transfer the frosting to a piping bag and frost your cupcakes!!!