Talk about caramelisation in terms of cookery, and we think of the classic dessert, creme caramel, nowadays almost forgotten, sad to say. But in recent years, caramelisation - creating a crisp crust on the surface of a food by browning it at a high heat - has been a favourite chef's technique, used to demonstrate not just exemplary culinary technique, but also - to quote the dynamic Cavan chef Neven Maguire - used as a device "to add texture and to add flavour, simply because the brown bits are sweet. Just think of the taste of an onion which has been slowly caramelised. Two of my favourite things to caramelise are scallops and salmon, and really it's what we might call the crispy bacon effect." For Robbie Millar, the luminary chef of Shanks restaurant in Bangor, the effect is even more elemental: "If I think about it, fundamentally it all goes back to my Dad making toasted marshmallows on a long fork over the fire when I was a kid. Every time I see a caramelised scallop, it reminds me of a toasted marshmallow."
When we brown food, we set up what scientists call the Maillard reaction, named after one of the first French scientists to study the subject in the early part of the century. When the natural sugars of food are being caramelised at high heat, we are setting off numerous chemical reactions which generate very complex mixtures of flavour molecules - cooked food contains between 300 and 800 flavour compounds, according to modern analysis.
Just recently, frying a pair of fillets of sea trout, I tried out the technique for crisping the skin as related to me by Maguire. Here is how you do it.
`Scale the fish, and then pat the fish dry with kitchen paper, then cut tiny slits in the skin with something like a Stanley knife, as this helps in two ways; one, the fish doesn't curl up when it hits the heat, and, two: it helps to cook the fish evenly. Season the fish. I use a heavy, cast-iron saucepan, and splash in a little extra virgin olive oil. I use olive oil because it can take a higher temperature than vegetable oil, it won't burn as easily.
"Don't use much oil, just pour it in and swill it about until you have a light coating. Then, get the pan really hot: it has to smoke. To make sure something like red mullet doesn't curl, I also hold the fish down with a pallet knife while it cooks. I then cook it for a good four minutes on the skin side, then I turn it over and then finish cooking the fish in the oven for a couple of minutes."
I found with the sea trout that this worked perfectly. I had not just an excellent piece of fish, but also the most delicious, crisp fish-skin. If you think fish skin isn't delicious, just try the technique, and you will be convinced immediately.
I served the fillets on top of some brown Spanish lentils, which had been cooked in ham water to add flavour, and made a rocket pesto, which has become my favourite sauce to serve with fish. To make this, simply place 3-4 ounces of fresh rocket leaves into the food processor with three peeled, seeded and chopped tomatoes and a couple of cloves of garlic.
Process and then drizzle extra virgin olive oil into the processor to achieve a sauce which has an emulsion-like consistency and gloss. Season with sea salt and freshly ground black pepper.
The crisping of fish skin seems to me one of the best ways to convince people to eat fish, and Robbie Millar's technique adds a few extra tips to Neven Maguire's practice:
"With salmon, I use butter. Even though oil will go to a higher temperature, I think butter gives you a nicer caramelisation, because it mixes with the natural sugars. I score the fish with small incisions to stop it curling up, then start it on the skin side at a high heat, then turn it over, then turn it back onto the skin side. One good chef's tip is to give the skin side a very light dusting of flour: just flour your hands and rub the skin side, no more. It just needs a tiny dusting."
Both Maguire and Millar agree "the best foods to caramelise are scallops, because their natural sugars and sweetness caramelise perfectly," as Maguire puts it. Millar adds: "Parsnip and salsify also caramelise beautifully. Foie gras is one of the best examples of caramelisation at its best. I cook it at such a high heat that the handle is practically dropping off the pan, and I cook it in a dry pan - there is enough fat in there already. When you put it in the pan, that smoke lets you know something is happening. I cook it very fast, turn it over, and it's ready when you have a crisp outside and a melting inside: to me, that's perfect."
That crispness concealing gooeyness is one of the great attractions of caramelised foods, as we find in this fantastic recipe for that classic dessert, creme caramel. In the making of a caramel, we find those flavour compounds which Robbie Millar mentions, for marshmallow is always one of the flavours we pick up when making a caramel, and also burnt toast, one of Robbie Millar's favourite things to eat. Marshmallows, crispy bacon, burnt toast, creme caramel. Who would have thought such cutting edge cooking could be so nostalgic?
Neven Maguire's Vanilla Creme Caramel with Apple Compote
Serves 4
4 eggs
2 egg yolks
120g (41/2 oz) caster sugar
400 ml milk
100 ml cream
1 vanilla pod Another 150g caster sugar
50 ml water
Preheat oven to 140C/Gas 2. Now, mix whole eggs, egg yolks and sugar together.
Bring milk, cream and vanilla pod to the boil. Pour into egg mixture and mix well.
Place sugar and water in a saucepan and boil together until golden brown and caramel in colour. Divide the caramel between four dariole moulds. Gently pour custard to the rim of the moulds. Cook in a bain marie in the oven for 30 minutes until set, then leave to cool.
For the apple compote
1 cooking apple, peeled and diced
100g caster sugar
100 ml water
Place the sugar and water in saucepan. Bring to a boil and add the apples. Bring back just to the point of boiling. Leave to cool.
Turn out the moulds onto a plate. Spoon apple around the creme caramel. Garnish with fresh mint.