Use your favourite chocolate bar for the topping.
If you use dark chocolate, then melt it with about ¼ cup of whipping cream for a creamier result. You can use shortbread, oatmeal or chocolate chip cookies instead of digestives.
Golden syrup is an English product that is heavier than corn syrup. It's available at the supermarket.
1 cup butter
1/3 cup Golden or corn syrup
300 grams digestive biscuits, processed into small chunks and coarse crumbs
1 cup chocolate chips
300 grams favourite chocolate bar (e.g. Toblerone, Dove), cut into pieces
Heat butter and Golden syrup together in a large pot over medium heat.
Add chocolate chips and stir until melted.
Add biscuits and stir to combine.
Turn mixture into an 8-by-8-inch pan lined with plastic wrap and spread smoothly.
Melt your favourite chocolate bar over medium heat until just melted. Immediately remove from heat and spread over base.
Cut into bars.