Make the graham crackers: In a stand mixer fitted with a paddle attachment, beat together butter and sugar until lightened in color, then fold in egg until combined. In a separate bowl, combine dry ingredients. In another bowl, whisk together molasses, honey, and milk. Add half the dry ingredient mixture to butter and sugar and beat to combine, then add half molasses mixture, scraping the bowl after each addition, and repeat with remaining dry and wet ingredients. Chill dough for at least 1 hour. The dough will very soft.