Oreo Cupcakes

Preheat oven to 350°F. Grease a regular muffin pan with nonstick spray or line with paper liners.
In a large mixing bowl, combine the flour, sugar, cocoa powder, instant coffee (if using), salt, and baking soda.
In another bowl, whisk together the egg, egg yolk and sour cream. Stir in the vegetable oil, followed by the coffee/water. Add to the dry ingredients and mix until incorporated.
Divide the batter into the muffin pan, filling each muffin tin no more than ⅔ full. Bake until cupcakes appear set and tops bounce back when gently pressed, about 15 minutes. Let cool a few minutes in the pan, then transfer to a wire rack to cool completely. Repeat with remaining batter, you should end up with about 15-18 cupcakes total.
Cupcakes can be made in advance and kept in an airtight container for up to 5 days, or in the freezer for several weeks (thaw before frosting).

In the bowl of a stand mixer fitted with a paddle attachment, or in a large bowl with a hand-held mixer, mix the powdered sugar, butter, salt, whipping cream, and vanilla extract on low speed until it starts to come together. Increase speed to high and beat for 3-4 minutes until frosting is fluffy, pausing once or twice to scrape the bowl down.
Add Oreo crumbs and mix on low until combined. If the frosting seems too stiff, add more cream or milk 1 tablespoon at a time as needed to loosen it up.
Frost cooled cupcakes with the frosting as desired. Top each with an Oreo. Frosted cupcakes will keep in an airtight container at room temperature for about 5 days after baking cupcakes.