Prepare everything for quick mixing. Crush the crackers and measure the vanilla and Biscoff (or nut butter). Grease an 8x8 or 9x9 casserole pan.
In microwave or on stovetop, melt butter in a large bowl or pan. Add marshmallows and continue to heat on low; in microwave, heat for 25 seconds, stir, 25 more seconds, stir, until everything blends together.
Add the vanilla extract and Biscoff, then the crumbs. Stir until everything is well blended. Glop it into the prepared pan. Use a piece of wax paper and a glass or firm spatula to compress everything.
To add some topping for oomph, melt the chocolate and drizzle it over the treats. Immediately sprinkle some salt over it all.
Let set for an hour or so, until firm. Cut into small squares.
OM NOM NOM!