A generous 1 3/4 cups semisweet chocolate chipsdivided
2large eggslightly beaten
1Tbsppure vanilla extract
Combine the sugars, arrowroot powder, baking powder, salt, cocoa powder, and 1/4 cup of the chocolate chips in a medium-sized bowl and whisk to incorporate.
Add the eggs, yolk, and vanilla to the dry ingredients and whisk vigorously — I did this for at least 3 minutes (taking breaks, yes). Or use a stand mixer.
Melt 1 1/2 cups of the chocolate chips and the vegetable shortening in a double boiler over medium heat (be careful about steam or water droplets getting into your melting chocolate).
Once melted, remove from the heat and add to the egg and sugar mixture, and whisk to incorporate. Cover the bowl with plastic wrap and place in the refrigerator for at least 24 hours. These cookies get better the longer they rest prior to baking.
When ready to bake them, preheat the oven to 350-degrees. Scoop the dough with a small (around 1 1/2 Tbsp) cookie scoop onto a parchment-lined cookie sheet. Place the sheet in the refrigerator again, briefly.
Bake the cookies, one tray at a time, for about 9 minutes (for a slightly underdone cookie) and up to 11 or 12 for a crispier cookie.
Repeat with any additional cookie dough. Cookies should be eaten warm (if you ask me), and so I recommend only baking as many as you want to eat at that time.
The cookie dough MUST set-up for at least 24 hours — longer is even better — so plan accordingly!!