I make English toffee for sweet tables and one problem I've had since I started is that the chocolate and toffee separate when I break up the toffee.
I cook my toffee in stainless steel (copper is no longer an option since our cooktop is now induction) and cool it down on butter greased marble counters. Once it's poured and hardened, but not cool, I pour over chocolate wafers or chips, depending on what the client has asked for. These usually melt within 5 minutes at which time I use an offset spatula to spread them over the toffee and sprinkle with toppings and drizzle with contrast chocolate.
This is popped into the fridge for half an hour to harden the chocolate.
Then I break the pieces by hand and at this point, the chocolate topping and toffee go their separate ways on about 25% or more of the toffee.
How do I prevent this?
I'm not sure of the best way to help you, but perhaps you could break up the toffee first and then dip it in chocolate? That's the way I do mine. Maybe someone else has had this problem and can help you figure out a solution!
I would try scoring the toffee part way through with a dough scraper just before pouring on the chocolate.
Perhaps this will help give it somewhere to 'crack' without putting so much tension on that top layer of chocolate.
The last time I made this i don't remember having the chocolate separation troubles but i can see how it could happen.
Note, after putting on the chocolate, letting it melt and spreading it I topped mine with some thinly sliced almonds. Maybe that helped???
I'm not sure if it makes a difference, but I pour mine into a greased jelly roll pan then top with chocolate. I let it set up on the counter, then break it up and store in an airtight container in the pantry. I haven't had any problems doing it this way.