In a small skillet over medium heat, melt butter, cooking until browned. Crush graham cracker into crumbs (I stuck it in a bowl and mashed on it with the end of the wooden handle of a spatula) and add to the pan, stirring to coat all the crumbs with the butter. Cook a minute or two, until crumbs are toasty. Remove from heat and set aside.
To make creamy layer:
Mix greek yogurt and maple syrup and vanilla-bean paste (or vanilla extract) until fully combined.
To make smoothie:
In a blender, blend cashew milk, lime juice, vanilla extract, spinach, maple syrup, chia seeds, banana and ice until smooth, about 90 seconds or so, depending on your blender.
To serve:
Layer smoothie and greek yogurt and top with graham cracker crumbs.