Line a 9 x 13” pan with parchment paper and set aside
Preheat oven to 350° F
Chop 1 ½ bars of chocolate into chunks. Set aside.
In a large bowl, stir together oats, cereal, cracker crumbs, and 1 ¼ cups of marshmallows (reserving the rest for topping). Set aside.
Combine butter, maple syrup, brown sugar, and salt in medium pan. Cook on low/medium heat, stirring frequently until everything is melted. Once the mixture starts to bubble, stir consistently. Let gently boil for 3 minutes while stirring. If the boil gets too aggressive, turn down heat. After 3 minutes, take off heat.
Add in ground flax seeds and stir well to combine.
Pour the hot liquid mixture into your dry ingredients and mix until combined.
Add in chocolate chunks and stir to combine.
Press mixture into your parchment lined pan. Start with the back of your spoon to spread out mixture. Then use the bottom of a jar or glass to firmly pack the mixture into the pan. Do this for 2 - 4 minutes.
Top with more mini marshmallows if desired (this is mostly just for looks and is optional).
Bake for 10 minutes.
Let cool in pan for 30 minutes on cooling rack.
Refrigerate for 2 hours before cutting. This chilling time allows them to set and helps keep them from crumbling apart when cut.
Slice into bars.
If you want a chocolate drizzle on top chop ½ chocolate bar and melt in microwave in 20 second increments. Stir well between each increment. Stop microwaving when there is still a bit of solid chocolate remaining. You should be able to get it to melt just by stirring well. Drizzle on top of bars as desired. I like to use a metal spoon for this.
Store cut bars in refrigerator.