Prepare the cookie dough: In a large bowl, use an electric mixer to combine the butter and sugars on medium speed until light and fluffy (2 to 3 minutes). Add the vanilla and milk. Mix in the flour and salt and beat on low speed until incorporated.
Spread about 1 tablespoon of dough onto 12 of the graham cracker halves. Break the chocolate bars into 12 equal pieces, and center one piece atop each mound of cookie dough
Toast the marshmallows over an open flame until golden brown. Place a hot marshmallow on top of the cookie dough and chocolate and top with remaining graham crackers. Gently press until the marshmallow begins to ooze out the sides. Let sit for 30 seconds to soften and melt the chocolate. Eat!
Notes
How to HEAT TREAT flour to make it safe for consumption: Toast your flour in the oven before using in this recipe. You’ll just put the flour in a pan and toast it at 350 degrees. F. for 5 minutes. That will kill any potential bacteria in the flour, and you can feel safe to use it in an uncooked cookie dough recipe.