Beat butter and sugar until light and fluffy. Add flour and mix to form a soft dough. Knead lightly then press into pan, smoothing base. Prick with a fork and bake for 30-35 minutes. Allow to cool.
Place filling ingredients in a saucepan and heat slowly, stirring, until sugar has dissolved. Bring to a boil and simmer for 7-10 minutes, stirring until it thickens. Cool and pour over base and leave to set.
Break up chocolate and add cream; place in top of double boiler to melt or place in microwave to melt 2 minutes watching carefully. Spread over caramel and let set.
*note* Lile's syrup can now be found in some stores that have international aisles. However, back in the day, had to find something to sub with. Yellow Label syrup makes an ok substitute, it is corn syrup with honey, and it is a bit different but will work as will karo. However, if you want the closest thing to it mix molasses with plain corn syrup in a 1:2 ratio. So for this recipe you would mix 1 tablespoon molasses with 2 tablespoons corn syrup.