Step 1: Preheat oven to 350 degrees Fahrenheit and Pam spray a 9x13 deep pan.
Step 2: Mix graham crackers, melted butter, cardamom powder, and vanilla extract with a spoon until the graham crackers are no longer loose crumbs.
Step 3: Spread the graham cracker mixture to make the crust in the pan, tightly packing it together and making sure it’s even.
Step 4: Bake in the oven for 10 mins or until it starts to become a darker brown.
Step 5: While the crust is baking, boil the ingredients for the syrup together until the sugar dissolves. Let it cool for 5-10 mins and then soak the marshmallows in that syrup in a separate bowl for 5-10 mins.
Step 6: Turn the oven off and lay the Hershey's bars on top of the crust. Pop the pan into the warm oven for about 2 minutes.
Step 7: Add the marshmallows in an even layer on top of the Hershey's chocolate.
Step 8: Broil the s’mores for 1-2 minutes until the marshmallows brown. Do not step away from the oven as this will happen very quickly! Top with crushed pistachios for an extra flavor crunch!
Cool the s’mores and slice them up into 12 or 24 bars using a wet knife. Store them in the fridge for a more hardened but still delicious bars before serving!