Preheat oven to 375 degrees. Line bottom of a 9-by-13-inch baking dish with graham crackers, breaking them to fit if necessary. Bake until crackers are lightly toasted and fragrant, about 8 minutes. Sprinkle with almonds and dollop with marshmallow creme.
In a heatproof bowl set over (not in) a pan of simmering water, combine chocolate chips and condensed milk. Cook, stirring occasionally, until chocolate melts and mixture is smooth. Pour chocolate mixture over marshmallow creme; working quickly, swirl together with a thin-bladed knife. Refrigerate until set, about 1 hour. Cut into 18 squares.
Refrigerate, tightly wrapped in plastic, up to 2 days.