Preheat your oven to 350°F (175°C) and line a cupcake tin with paper liners.
In a large mixing bowl, combine the almond flour, erythritol or sweetener, cocoa powder, baking powder, and salt. Whisk until well combined.
In another bowl, mix together the unsweetened almond milk, melted coconut oil or butter, vanilla extract, and sour cream or Greek yogurt until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
If making chocolate cupcakes, fold in sugar-free chocolate chips and instant coffee to enhance the flavor.
Spoon the batter into the prepared cupcake liners, filling each about two-thirds full.
Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
While the cupcakes cool, prepare the frosting by beating together the softened cream cheese and butter in a bowl until creamy.
Gradually add powdered erythritol and continue to beat until combined and fluffy. Add vanilla extract and enough heavy cream or almond milk to achieve desired consistency.
Once the cupcakes are completely cool, frost them generously with the cream cheese frosting.