Melt 4 ounces semi sweet chocolate on the stove or in the microwave and cool slightly.
Combine the mascarpone, powdered sugar, coconut milk, 3 tablespoons kahlua (if using), melted chocolate and vanilla in a large bowl. Beat with a mixer on medium speed until creamy, light and fluffy, about 2 minutes.
Add the coffee and the remaining Kahlua to a shallow bowl. Lightly dip the pieces of Hawaiian bread through the coffee mixture and allow any excess coffee to drip off.
To assemble add a layer of coffee dipped Hawaiian bread to the bottom of 4-6 serving glasses or 1 serving bowl. Spread a layer of the mascarpone over the bread and then add a finely chopped chocolate. Repeat the layers until all the ingredients have been used. Cover with plastic wrap and refrigerate at least 1 hour or overnight. Garnish each individual tiramisu with a dollop of coconut whipped cream and a good sprinkle of chopped chocolate. Dust with cocoa and or matcha powder. Serve!