Beat butter and sugar with electric mixer on medium speed until light and fluffy. Beat in egg and vanilla. In a separate bowl, mix together both flavors of crushed graham crackers, flour, and salt. Stir the graham cracker mixture into the butter/sugar/egg/vanilla mixture. Should become one, big crumbly clump.
Press about 1/2 cup or more, if needed, of the graham cracker mix over the bottom of the greased 13x9x2-inch baking pan. Sprinkle half (1 cup) of the chocolate chips on top. Sprinkle 3 cups of the mini marshmallows on top. Crumble, by hand, the rest of the graham cracker mix on top. Sprinkle last 1/2 cup of the mini marshmallows on top and finally, sprinkle the rest (1 cup) of the chocolate chips on top.
Bake for 25-30 minutes or until brown.