Instructions

To make the frosting:

1. In a medium sized sauce pan heat the cream over medium/high heat until it begins to simmer.
2. Remove from the heat and whisk in the white chocolate, add the key lime flavor oil and whisk until smooth.
3. Transfer the mixture to a glass mixing bowl and cover with plastic wrap, making sure to press the plastic to the surface of the chocolate mixture.

To make the shortbread:

1. Butter a quarter sheet pan or 9"x13" pan and set aside.
2. In a microwave safe bowl melt 4 oz of the white chocolate for 1 minute, stir until smooth.
3. In the bowl of your stand mixer fitted with the paddle attachment beat the butter and sugar on high for 3-5 minutes.
4. Add the melted white chocolate to the butter mixture and blend well.
5. Add the cake flour and the remaining 4 oz of white chocolate to the bowl and mix until it comes together.
6. Press the dough evenly into the butter pan and freeze for 15-20 minutes.
7. Preheat your oven to 325º F, bake the shortbread layer for 20-23 minutes, remove carefully and let cool completely.
8. While the shortbread is cooling, place the key lime frosting mixture in the refrigerator for 20 minutes.
9. Then using an electric hand mixer beat the key lime frosting over high speed for 3 minutes, scraping down the sides of the bowl until the frosting becomes a pale white color.
10. Spread the frosting over the cooled shortbread layer and evenly sprinkle on the lime zest.
11. Slice and serve, store leftover shortbread bars in an airtight container in the refrigerator for up to 1 week.