Coffee syrup: in a small saucepan combine water, sugar, and coffee powder. Bring to boil, reduce heat to a simmer. Cook 5 minutes until mixture begins the thicken. Set aside to cool.
Filling: In a small bowl beat whipping cream until it holds soft peaks. In a separate bowl (no need to wash beaters) beat Mascarpone cheese and powdered sugar until creamy. On low speed, beat Mascarpone mixture into whipping cream.
Assembly: Use shortbread cookies, or cut rounds from pound cake as Tiramisu base. Brush each base with coffee syrup and place in a mini muffin liner. Spoon or pipe Mascarpone cream over each base completely covering the cake or cookie. Generously dust with Brown Dog Riba-Riaba Rub, refrigerate at least 4 hours - best to let flavors blend overnight.