Preheat the oven to 180C/350F. Line a square pan with parchment paper and set aside.
In a large mixing bowl, combine your shortbread crust ingredients and mix well. If the batter is super crumbly, add a dash of extra syrup or milk of choice.
Transfer the batter into the lined pan and press firmly into the base. Bake for 17-20 minutes, or until it begins to get golden. Remove from the oven and allow to cool.
While the shortbread crust is cooling, prepare your toffee. In a non-stick saucepan, combine your monk fruit and butter and heat on low, stirring regularly. Once the mixture begins to bubble, insert your candy thermometer into the center. Stir every 30 seconds or so. Once the thermometer reaches 300C (hard crack), remove it from the heat. Continue stirring briskly for around 30 seconds, before pouring on top of the shortbread.
Let the toffee sit for several minutes. After that, top with chocolate chips. Cover with tin foil for 5 minutes. After 5 minutes, spread out using a rubber spatula. Refrigerate for several hours, until firm. Slice into bars.
To store. Store these chocolate toffee bars in a sealed container, at room temperature. It will keep fresh for at least 2 weeks. You also have the option to refrigerate it, and refrigerated toffee bars will keep for at least 4 weeks.
To freeze. Chocolate toffee bars are freezer friendly and can be stored in the freezer. Place the toffee bars in a ziplock bag or shallow container. Frozen toffee bars will keep fresh for at least 6 months.
To thaw. From frozen, allow toffee bars to thaw at room temperature or in the fridge overnight.