Preheat the oven to 350 degrees F and line a muffin tin with cupcake liners and set aside.
In a large mixing bowl, beat together the eggs, granulated erythritol, heavy cream, and vanilla with a fork. Mix in the almond flour, cocoa powder, baking powder, and salt.
Use a medium cookie scoop to portion out the batter into the cupcake liners. I use 2 level scoops (about 3 tablespoons) of batter total per cup.
Bake for 15 to 18 minutes or until a toothpick comes clean from the center. Remove from the oven and transfer the cupcakes to a cooling rack to cool completely before frosting. (see note)
Frosting
Add the heavy cream, chocolate chips, erythritol, vanilla, and salt to a large bowl. Microwave on 30-second intervals, stirring between each one, until a rich ganache forms.
Transfer the ganache to the refrigerator and chill for 1 hour.
Add the chilled ganache to a stand mixer bowl or use a hand mixer to beat the ganache until it's light and fluffy, scraping down the bowls as needed. This will take about 5 to 7 minutes.
Transfer the whipped ganache to a piping bag fitted with a piping tip and pipe onto the cooled cupcakes. Store in an airtight container until ready to serve.
Notes
The carbs listed for each cupcake with frosting is 36 grams. After subtracting the sugar alcohols and dietary fibers from the erythritol and dark chocolate chips, each cupcake has a net carb amount of 14.4 grams.
I like to start making the frosting while the cupcakes are baking. Then by the time I'm done chilling and whipping the frosting, the cupcakes are cooled enough to frost.