Hot Cocoa Cookies

In a medium mixing bowl, stir together the flour, hot cocoa mix, baking powder, cinnamon, and salt, then set aside.
In a large bowl, use an electric mixer to beat the butter, granulated sugar, and brown sugar on medium-high speed until well-combined and smooth (about 2 minutes). Add the egg and egg yolk and beat until combined. Add the vanilla extract, then scrape down the sides and bottom of the bowl with a rubber spatula.
On low speed, gradually add the flour mixture.
Fold in the chocolate chips with a rubber spatula.
Chill for about 1 hour, or until the dough is no longer sticky.
Meanwhile, preheat oven to 350°F and line baking sheets with parchment paper.
Using a spoon or a medium spring-loaded cookie scoop, drop 1 ½-tablespoon sized balls of dough onto the cookie sheets.
Bake for about 10 minutes, then remove from oven and top each cookie with a piece of semi-sweet chocolate and 1 marshmallow half, cut side up.
Return to oven and continue to bake for another 4 minutes, or until the marshmallow begins to melt slightly.
Remove from the oven and use a kitchen torch to toast the tops of the marshmallows. Alternatively, place the cookies under the broiler for about 30 seconds to toast the marshmallows. Be careful, as the marshmallows can go from toasted to burnt very quickly!
Let the cookies cool on the cookie sheets for 5 minutes before removing them to wire racks to cool completely.