To make the taco shells, preheat oven to 325° F. Line four baking sheets with silicone baking mats. Slide paper circles underneath the mats to use as guides for shaping the cookie shells.
Set up taco mold or place hard taco shells upside down on the sides of several loaf pans. Set aside.
Combine flour, sugar, cornstarch, and salt in a medium bowl. In a separate bowl, whisk egg whites, vegetable oil, water, and extracts until frothy. Add dry ingredients to the eggs and stir until the batter is smooth.
Spoon just under 2 tablespoons of batter in the center of each circle on a prepared baking sheets. Use the back of a spoon to smooth the batter evenly to cover each circle (it will be thin).
Bake the cookies for 8 minutes on the lower rack of the oven. While the shells bake, prepare another baking sheet with batter. After 8 minutes, shift the lower baking sheet to the top rack and place the second baking sheet on the lower rack. Bake for 8 more minutes, or until the shells on the top rack are lightly browned around the edges. Remove finished shells from the oven quickly and reshuffle the baking sheets in your oven to continue the baking process.
Working quickly and carefully while the shells are hot, slide a spatula under one of the shells and ease it off the silicone mat. Taking care not to burn your fingers, place the shell bottom-side up over a mold or taco shell, pressing it into shape as necessary. If it resists holding the proper shape, slide another taco shell over the top to hold it in place while you continue working. Repeat with remaining shells.
Continue baking shells until you’ve used all the batter.
Once the shells have set, remove them from the molds. Store cooled cookie shells in an airtight container until ready to use (they keep well for several days).
For the strawberry salsa, whisk together lime juice, jam, and salt in a medium bowl. Add strawberries and toss to combine. Add brown sugar to taste and toss to combine. Just before serving, mix in chopped herbs.
To prepare the cream cheese frosting, combine cream cheese and butter in the bowl of a standing electric mixer. Beat with the paddle attachment until smooth. Add confectioners’ sugar, vanilla, and salt. Mix on the lowest speed until combined. Increase speed to high and beat until smooth and creamy.
Divide the frosting between two bowls, leaving one bowl white for sour cream. To the other half, add several drops of green food coloring, as well as a small amount of brown and yellow food coloring to achieve the proper shade of green. Mix well. If the color looks too dark, add in some of the white frosting to lighten the color.
To prepare the taco meat, slice the gingerbread in half. Reserve one half. Working over a bowl, crumble one half of the gingerbread into irregularly-sized chunks. Depending on the amount of "meat" used to fill the tacos, you may need to crumble some of the remaining gingerbread.
To prepare the cheese, place a bar of white chocolate in the microwave. Heat in 5 to 10-second bursts until it warms enough to feel slightly flexible but not melted. Grate the chocolate carefully. If it crumbles as you work, give it some additional time in the microwave. Add the chunky end pieces that become difficult to grate into guacamole frosting. Repeat with remaining bar. If you want more texture in the guacamole, add some of the shredded cheese as well.
Slice the blueberries and cape gooseberries in half. Slice herbs into strips that look like shredded lettuce (these scissors
work great for this).
To assemble tacos, layer the filling ingredients into the taco shells, starting with a generous portion of crumbled gingerbread.
The shells will soften once they are filled, so be sure to prepare them close to serving time. Alternatively, set up a self-service impostor taco bar and let people customize their tacos.