Millionaires Shortbread - chocolate?

[HectorAndKiki]

Can I ask what chocolate does everyone use to top the caramel mixture - not sure whether to use cooking chocolate or buy something like Green and Blacks.

I know the cooking chocolate will melt easily, but it’s just mightn’t taste as nice ... really don’t want to spoil it.
Thanks

Green and Blacks. I use half milk chocolate and half dark chocolate as I find it too sickly sweet otherwise.

I wouldn't use the old fashioned cheap cooking chocolate but the real chocolate you sometimes get in the baking section is quite nice.

Thanks for the replies.