Directions:

For the Phish Food Cookies:

1. Pre-baking note: These cookies need to chill in the fridge for 2 hours before baking. This prevents them from spreading too much and ensures a fudgy center.
2. In a large bowl, cream the butter, brown sugar, and granulated sugar with a hand or stand mixer until light and fluffy. Add the egg, egg yolk, and vanilla, and mix until fully combined. 
3. Now mix your dry ingredients. In a separate bowl, whisk together the flour, cocoa powder, espresso powder, salt, baking soda, and baking powder. 
4. Gently fold the dry ingredients into the wet until just a few streaks of flour remain. Add the milk and chopped chocolate and fold until just combined. Do not overmix.
5. Using a 2-inch (about 3 tbsps) large cookie scoop, scoop the cookie dough into balls and place on a parchment-lined baking sheet. Cover the dough with plastic wrap and refrigerate for at least two hours. If you haven’t already done so, place the mini marshmallows in the freezer so they stay soft after baking.
6. Preheat the oven to 350°F. Working with chilled dough, flatten each portion and place a caramel and 6–7 frozen mini marshmallows in the center. Fold the dough over the filling to seal, rolling it back into a ball. It’s okay if a few marshmallows peek out, but cover as much as you can to keep the centers soft. Repeat with all portions.
7. Place the filled dough balls on a parchment-lined baking sheet, spacing them at least 3 inches apart. Bake in batches, keeping the remaining dough chilled. If you’d like, dot the tops with extra marshmallows or halved caramel pieces. 
8. Bake in a 350°F oven for 11–12 minutes, until the edges look set but the centers still appear soft.
9. Let the cookies cool on the baking sheet for 5 minutes—they’ll be very soft—then transfer to a wire rack to cool for another 5–10 minutes. Store in an airtight container at room temperature for up to 1 week, or freeze the unbaked dough balls for up to 3 months.