Preheat oven to 325 degrees F. Line 2 cookie sheets with silpat or parchment paper.
In a small bowl, whisk together the flour, salt, baking soda, and cinnamon. Set aside.
In the bowl of a stand mixer, cream butter and sugar with the paddle attachment until light and fluffy. Add the Biscoff or Speculoos butter and mix until combined. Add the eggs one at a time until combined. Mix in the vanilla extract.
Slowly mix in the dry ingredients until combined. Fold in the toffee bits.
Refrigerate the dough for at least 3 hours.
Scoop the dough onto the lined pans with a cookie scoop. Bake for 13-15 minutes or until golden brown.
Glaze: Melt the chocolate and vegetable shortening in a heat-proof bowl over a pot of simmering water, making sure the water doesn't touch the bottom of the bowl, until smooth.
Dip the cooled cookies into the melted chocolate and top with festive sprinkles. Allow chocolate to set before storing in an airtight container.
Recipe by The Messy Baker Blog at http://themessybakerblog.com/2012/12/09/chocolate-dipped-biscoff-pillow-cookiessundaysupper/