Spray a 9-inch square baking dish with cooking spray. Line with two pieces of parchment paper, crisscrossed and overhanging the sides of the pan.

Break the graham crackers into ¼-inch pieces and place in a large mixing bowl. Add 1 cup marshmallows and the almonds. Stir to combine.

Melt the butter in a medium saucepan over low heat. Once the butter has melted, add the remaining 1½ cups marshmallows, the chocolate chips, and the syrup. Cook, stirring, until everything is melted and fully combined, about 2 minutes.

Immediately add the chocolate mixture to the mixing bowl and, working quickly, stir well until everything is fully combined. Pour the mixture into the prepared baking pan and press down firmly. Refrigerate until firm, about 2 hours.

Using the parchment paper to help you lift the fudge from the pan, remove and place on a cutting board. Cut into small squares. Serve or refrigerate until serving.