Preheat oven to 350°F and line a muffin pan with paper or foil liners.
Whisk together the almond milk or milk and vinegar in a large bowl, and set aside for a few minutes to curdle. Regular milk will not curdle as clearly but it will still be fine! Then add the sugar, oil, and vanilla extract to the vinegar mixture and beat until foamy.
In a separate bowl, sift together the flour, cocoa powder, baking soda, baking powder, cinnamon and salt. Add in two batches to wet ingredients and beat until no large lumps remain (a few tiny lumps are OK).
Pour into liners, filling 3/4 of the way. Bake 18 to 20 minutes, until a toothpick inserted into the center comes out clean. Transfer to a cooling rack and let cool completely.
For the Frosting
Fill a medium saucepan with 1 inch of water and bring it to a simmer over medium heat.
Place the egg whites, sugar, cream of tartar, and salt in the clean bowl of a stand mixer and whisk by hand to combine.
Nest the bowl over the saucepan, making sure the bottom of the bowl is not touching the water. Heat the egg white mixture, whisking constantly, until the sugar has dissolved and the mixture is hot to the touch (about 120°F on an instant-read thermometer), about 6 minutes.
Transfer the bowl to a stand mixer fitted with the whisk attachment. Turn the mixer to medium and whisk for 1 minute. Increase the speed to high and whisk until stiff, glossy peaks form, about 5 minutes more. Add the vanilla and whisk until just incorporated, about 1 minute.
Pipe onto the cupcakes using a medium star tip. Chill (optional) for at least 30 minutes to set the frosting a bit, then use a kitchen torch to lightly brûlée the edges.
Chill (optional) for at least 30 minutes to set the frosting a bit, then use a kitchen torch to lightly brûlée the edges.