This is an I-can't-stop-spooning-this-straight-into-my-mouth-oh-****-down-my-dress-ah-who-cares-WANT-MORE-SAUCE sort of sauce.
Essentially, you make a dry caramel, then you stop it with lots of double cream, then you pour it over dark chocolate to make a caramel ganache (!!), then you add a bit of salt. Then the aforementioned spoon incident occurs.
It took a few tests to get the right ratio. The first time I didn't add enough cream or chocolate and it was way too thick. The second time I didn't have enough caramel and the chocolate was overpowering. The third time I hit on this combination and it's been reliably brilliant ever since.
At first I poured it over chocolate ice cream but I found that the flavour of the ice cream swamped the caramel and disrupted the balance. In the end I made a batch of my favourite vanilla ice cream, which works brilliantly.
When I started to churn the vanilla, I realised that I hadn't managed to get the base of my ice cream maker cold enough. After five minutes I gave up and scraped the slushy mixture into a box and froze it. I only stirred it up once with a fork but it still has a lovely smooth texture. I don't think the initial time in the ice cream machine did that much, so I reckon if you don't have one then stirring it around two or three times would give pretty good results.
I thought about adding extras - some raspberries for an acidic touch, some toasted flaked almonds for a textural crunch - but in the end simplicity won. It doesn't need anything else.
Choco-Caramel Sauce
55g white sugar (granulated or caster)
150ml double cream
40g dark chocolate (70-85%)
big pinch of fine sea salt
Sprinkle the sugar evenly over the bottom of a medium-sized, thick-bottomed pan. Turn the heat up to medium-high and watch carefully - after a few minutes, the sugar will start to liquify at the edges. Don't stir it - you can flick some of the crystals onto a liquid bit, but don't fiddle too much. Once it's nearly all melted and starts to caramelise, swirl it all together. Keep heating until you have a deep golden-bronze colour (see above).
Take off the heat then pour in the cream and vigorously stir it in as it bubbles up (watch out, it is very hot). If you have a few clumps, whisk them in while it is still hot. Leave for a couple of minutes to stop bubbling and cool down a bit. Chop the chocolate up into small chunks and place in a small bowl. Pour the caramel over the chocolate, then leave to sit for a minute before stirring into a glossy sauce. Add the pinch of salt and stir through.
Pour over ice cream while warm - if it cools down too much and becomes too thick, pour some boiling water into a slightly bigger bowl and immerse the sauce bowl in it for a minute or two. Stir till smooth (dip again if it's still too thick). The sauce will keep in a covered bowl in the fridge for 4-5 days.
(Makes one bowl, probably enough for 3-5 sundaes, depending on size. If you don't eat it all first.)
Three more recipes that involve a dry caramel:
Salted Caramel Brownies
Cider Caramel, Sautéed Apples and Cinnamon Ice Cream
Salted Caramel and Walnut Braided Bread