General purpose chocolate sauce

Hot chocolate season is upon us and we're out of Hershey's syrup. So, I took a shot at my own:

heated and immersion blendered:

dark chocolate unsweetened powder, 3/4 C
sugar, 1C
water, 1C
sweetened condensed milk, about 3 oz

It's a little thin but tasty. I added about 2 oz of this and 4 oz of milk and steamed it using one of these.

Anyone else got a good general purposed chocolate sauce recipe?