Heat butter, condensed milk and syrup together. Cool
Heat topping ingredients together and set aside to cool.
Beat egg with sugar and vanilla, add melted butter and dry ingredients including chopped nuts.
Spread into greased sponge roll tin.
Reserve a little mixture for crumbling.
Spread cooled caramel mixture over base then crumble remaining mixture over top.
Bake 30mins in oven 175 C.
Cut into squares when cold.