In a saucepan or microwave safe bowl, whisk together almond butter, maple syrup, vanilla extract, pumpkin spice and salt. If using a saucepan, bring to a low simmer and constantly stir, cooking to reduce down the mixture slightly. If using a microwave, microwave for 30 seconds, remove and whisk and repeat 2 more times.
Once your mixture is slightly reduced and a little bit thicker in texture, slowly add in cereal a cup at a time. Start with less and add more as you go, in order to avoid ending up with a mixture with too much cereal (it won't hold together if this happens, as it will be too dry).
Transfer the mixture into a lined 8x8 dish, gently pressing down and flattening. Optionally, drizzle with melted dark chocolate then pop into the refrigerator for at least 30 minutes to set. Slice and enjoy!