Grease a 8x8 square baking pan well. Add the cookie crumbs to a bowl. Add the melted butter and stir it into the crumbles until everything is wet. Press the shortbread mixture into the pan in an even layer. Refrigerate until firm.
To Make the Caramel Layer
Add all caramel ingredients to a small saucepan and bring to a boil. Reduce the heat to low and simmer until thickened while stirring often. Pour over the hardened shortbread base and refrigerate again until cold (else the chocolate will mix with the caramel).
To Make the Chocolate Layer
Melt the chocolate together with 1 tablespoon butter. Pour over the caramel layer and refrigerate until hardened. Cut into bars.
Video
Notes
Ingredient Notes:
Condensed Milk: Do make sure to use the sweetened condensed milk and NOT evaporated milk, because the evaporated milk takes a lot longer to turn into caramel.Chocolate: Feel free to use your favorite chocolate chips for the topping, we like semi-sweet best but milk chocolate or dark chocolate work, tooShortbread: I only tested these with Walker’s Shortbread, so If you use a different brand you may see different results
Cooking Tips:
Caramel: Some commenters have noted that the caramel never thickened for them. This is most likely due to brand differences, or due to using evaporated milk instead of condensed milk. As a little troubleshooting if your caramel won’t thicken, put it back on high heat (be careful not to burn it!) and let it get bubbly until you notice it starts thickening. Then you can turn the heat back down.Chilling: Do make sure to stick to the chilling times in between the layers, or they may end up mixed together.Slicing: They are quite solid after chilling, so let them sit at room temperature for a bit before slicing.
Storage tips
I like to store them in the fridge for around 5 days, because there they keep best.But do make sure to remove them around 30 minutes before serving, because they taste best at room temperature (they’re quite hard to chew when they’re completely chilled).You can also freeze them for up to 3 months, if you want to make them ahead.