Line an 8-inch square pan with parchment paper.

Crush the pretzels and caramel rice cakes into small pieces (not powder).

In a microwave-safe bowl, combine the cashew butter, maple syrup, vanilla, and optional salt. Microwave 20 to 30 seconds until just warm and stir until smooth.

In a large bowl, combine the crushed pretzels and rice cakes.

Pour the warm cashew butter mixture over the dry ingredients and stir until evenly coated.

Let cool 2 to 3 minutes so it is warm but not hot.

Fold in the mini marshmallows gently so they stay whole.

Press firmly into the prepared pan.

Refrigerate at least 1 hour before cutting into bars.