That takes the biscuit

It's a never-ending quest for the perfect cheesecake topping.

I have spent my adult life searching for a cheesecake as good as the one I used to eat as a student in Exeter. It was on the menu of a restaurant called Bananas and had a firm, chocolatey, biscuit base, and a mousse-like, lemony topping. The alliance of crunchy biscuit and light mousse - tangy but not sour - was unimprovably good.

This was not what most people would call a proper cheesecake. A proper cheesecake is a creation from central Europe, baked with a filling comprised of curd cheese, eggs, lemon juice and zest, and perhaps sultanas. It has a topping of soured cream. You can get, budget permitting, a superb example at the Wolseley, the restaurant in Piccadilly, London that models itself on central European brasseries. This cake is luxuriously rich and creamy: so rich and creamy that a slice of it is almost too much of a good thing. But my highest-ranking foods compel me to carry on eating them beyond the point of satiety.

Then there is New York cheesecake, baked with cream cheese and often having a mouth-coating consistency that I find a little oppressive. Wikipedia tells me that there are Chicago, Pennsylvania, Philadelphia and Ann Arbor variations. But my quest is for something lighter.

I am making good progress towards the ideal base. It does not have to be chocolatey, but it must be firm: a soggy cheesecake base is a dispiriting thing. Delia Smith, aiming for the same texture, recommends mixing the biscuits with grapenuts cereal. I find, though, that a combination of two parts crumbled digestives - American recipes refer to "Graham crackers" - to one part butter, compacted on a base and put in the freezer for a while, produces a satisfying crunch. My next experiment will be to discover whether the advice of some recipes - that you bake the base before chilling it - works even better.

The filling is more problematic. In my book Don't Sweat the Aubergine, I gave a recipe involving cream cheese, cream and condensed milk, along with lemon and lime. I stand by it; but it does not have the foamy quality of the Bananas paradigm. I have tried, too, something called orange and lemon mousse cake, and - without the grapenuts - Delia's key lime pie. The results were similar.

My latest experiment was prompted by A A Gill, who referred dismissively to Sloaney cooks supplying dinner parties with cheesecakes made from Philly cheese and lemon jelly. Instead of thinking, as I was supposed to, "How vulgar," I thought: "I must try that." Googling the ingredients, I found a recipe on Delia Smith's messageboard. The cake tastes of gelatinised condensed milk: delicious in its way, if slightly sickly. I am not there yet.

Perhaps I should forget the cheese, and just prepare a base and tip some lemon mousse into it.