For the cupcakes: Preheat the oven to 325 degrees F.Line muffin pans with 24 muffin liners. In the bowl of an electric mixer with the paddle attachment, whisk both flours, the granulated sugar, baking powder and salt until well combined. With the mixer on low speed, add the butter.
Add the eggs, one at a time, scraping the bowl as needed.
Add the milk, rum and vanilla, and mix for about a minute until well combined.Fill the prepared muffin pans three-quarters full with batter and bakeuntil a toothpick inserted comes out clean, about24 minutes.
Combine the hot coffee, granulated sugar and rum in a bowl and whisk until the sugar dissolves. Refrigerate until cool.
For the frosting: In the bowl of an electric mixer with the whisk attachment, combine the whipping cream and marsala and whip until stiff peaks form. In another bowl, mix the mascarpone cheese and powdered sugar with a wooden spoon until well combined. Fold the mascarpone mixture into the whipped cream and refrigerate until use.
To assemble: Use a pastry brush to soak the cupcakes with the rum coffee syrup, soaking twice. Top with whipped cream marsala mascarpone frosting.
