Line a loaf pan (either 8 or 9 inch will work; one will be taller, the other longer). You can either line with heavy duty plastic wrap or spray non-stick with a parchment sling. Set the pan aside
Break the cookies into pieces of different sizes; no bigger than a bite; no smaller than a bean. You don't want cookie dust. I do this by hand. If you can use the Ziploc bag/mallet method without making dust, have at it. I think I use it too much as a therapy session and get very little useable cookie action... though do feel better. Set the cookie bits aside.
Put a large saucepan (that will eventually hold all of the ingredients, including cookies, over medium heat and melt the butter. Either remove from the heat or let it brown a bit if you'd like browned butter. It'll give a toasty flavor which is delicious. I did not brown the butter this go.
When melted (or browned to you liking, remove from the heat.
Add 12 ounces of the bittersweet chocolate chips and all of the Lyle's or Karo syrup. Let sit a few minutes to melt and then stir until smooth and shiny.
Add the cookie bits and stir bottom-to-top until all of the cookies are coated. Be quick but gentle.
Pour half of the chocolate cookie mixture into the prepared pan and press firmly so that all of the corners of the pan are filled. Put the remaining mixture in and press down firmly. I put a piece of parchment down and use a second loaf pan to do the pressing. I keep the parchment there and then cover the entire loaf pan in plastic wrap.
Refrigerate for a few hours or overnight until the cake is solid.