Mini Lime Cheesecakes

I bought a stack of limes the other day to make some ice cream but whilst tryingto find an old recipe I came across this one and the ice cream quickly morphed into cheesecake.

This is based on a Nigella Lawson recipe which I fiddled with a little to avoid a visit to the shops.

100g unsalted butter
230g digestives
2 large eggs seperated
200g can condensed milk
1 tblsp casterrsugar
zest and juice of 2 limes
pinch of salt

Oven at 170.
Crush the biscuits, I used my mortar and pestle as its big enough. Melt the butter then stir the biscuits into the butter untl they are well combined.
Depending on what size cakes you want push the crumb mixture firmly into the bottom. I used mini muffin tins, this is enough for 2 x 12 trays. I filled the tins to half way but before you press it in it pretty much filled each hole. This would work for 1 x 12 regular size tin also and likewise for single large cake.
Put the filled tins into the fridge for the butter to set while you continue with the rest.
Beat the egg yolks until thick add, whilst beating, the condensed milk the sugar the lime juice and half the zest. keep the rest of the zest in an air tight bag in the fridge if you are going to erve them the next day.
In seperate bowl whisk the egg whites with the salt until soft peaks form and gently fold into the yolk mixture.
With a dessertspoon fill the biscuit crusted tins. Dont go beyond the top of the hol. a couple of mine did and they were difficult to get out without trashing.
Transfer to the oven and cook for 10 mins. Remove and let cool in the tins then refridgerate for a day.
Before serving top with rest of zest.