Add the eggs, avocado oil, and water in a stand mixer bowl or a large bowl. Add the flour and whip until combined. Add in the brownie mix and whip until combined. Whip for two minutes until combined, and the mixture turns pale yellow.

Make equal-sized cookie dollops on a lined sheet pan with a cookie scoop or tablespoon. Please make sure there are 2 inches between each cookie because they spread in the oven. Once all your cookies are on your sheet pan, slam your pan down on your counter to spread out the dough. You will want to slam it about 3 to 5 times. Place in the preheated oven. For: Chewy cookies, bake for 12 minutes; Crispy cookies, bake for 15 minutes.

Remove from oven and let cool on pan for about 10 minutes, until it's easy to remove the cookie. When making chewy cookies, you will need to move gently not to tear the cookie. Set cookies aside and cool completely before assembling sandwiches.

While the cookies are cooling, make the filling. Add one container of vanilla frosting and 1 tablespoon tahini into a stand mixer bowl or large bowl. Whip for 3 minutes until frosting is fluffy.

To make the sandwiches, find cookies that are similar in size and pair them together. Pipe or spread about 2 tablespoons onto one cookie and top with a similar-sized cookie. You can place the cookies in the fridge to make a great cold treat if it is warm out.‍