Roast the almonds and pistachios in an oven heated to 400 F for 10 minutes, stirring occasionally.
Lightly grease a 9 x 13 baking pan, and line with rice paper.
In a stand mixer, whisk the egg whites until stiff.
Combine sugar and water, and boil in a small sauce pan over medium until it reaches 250 -265 F.
Add honey. The temperature will drop. Let cook until it reaches 280-290 F.
Meanwhile, beat the eggs again quickly, to ensure peaks are still stiff.
Once the sugar mixture has reached temperature, turn the stand mixer to medium and slowly add the sugar mixture. Once fully incorporated, add the vanilla extract then whisk on high for 1 minute. Switch from the whisk attachment to the paddle. Beat at medium-high for 5 minutes.
Add roasted nuts and powdered sugar. Mix until incorporated.
Pour batter into the prepared pan. It will be thick and unruly, so it may be wise to have a helping hand nearby. We recommend using a greased spoon or spatula as it will stick to everything.
Smooth out the batter, then top with a sheet of rice paper. To smooth it out further, use a rolling pin over the rice paper.
Allow to cool at least 3 hours, but ideally overnight.
Transfer to a cutting board to slice into strips and chunks of desired size. Wrap with cellophane or wax paper to keep.