Shortbread & Peanut Butter Crust Lime Tarts

Someone gave us a box of handmade, all-butter Scottish shortbread which unfortunately has gone uneaten. AK and I are not really fans of shortbread, which we find rather bland and slightly too rich for our humbles palates. I also happened to have a pack of roasted peanuts. So I decided to try something out. I whizzed the shortbread and shelled nuts in the processor, added a bit of melted butter and pressed it into tart cases. I baked the cases in the oven at 160 deg C for 15 minutes, and voila, peanut-buttery tart casings.

For the filling, I knew I wanted to make a tart, creamy lime version ala key lime pie. I pored through Dorie Greenspan's Baking: My Home to Yours and Martha Stewart's Baking Handbook, both of which called for condensed milk in their pie filling recipes. I have made desserts with condensed milk before, and really dislike the sickly-sweet, sticky aftertaste, which I find overwhelming. So instead I reduced a cup of milk and a couple of tablespoons of sugar and added this to some beaten egg yolks. I reduced the custard to a thick consistency, and then stirred in the lime juice. I then reduced that further to a thick, spatula-coating mixture before straining the mixture into the tart cases and then baking the whole lot again at a very low heat.

The result? Exactly as I wanted - creamy, tart lime filling juxtaposed against a rich, crunchy peanut-flecked, peanutty crust.

For the crust:

1 1/2 cups shortbread cookies
1/2 cup roasted peanuts
3 tbsps melted butter, cooled

For the filling:

1 cup whole milk
5 tbsps granulated sugar
1/2 cup lime juice
3 large egg yolks

To make the crust, whiz the cookies and peanuts in the food processor. I found that the peanuts started forming peanut butter very fast (another experiment for another time), so pause and stir in between whizzes. Add the melted butter, whiz to mix then press the mixture into 6 tart casings. Bake at 160 deg C for 15 minutes. Cool slightly then pop them in the fridge while you get started on the filling.

For the filling, place the milk in a thick-bottomed saucepan with the sugar and reduce over a low heat until the mixture is about half its volume. Whisk the egg yolks then slowly add the hot milk mixture, whisking all the time. Return the mixture to the pan and add the lime juice, stirring all the time. Reduce the mixture until it thickly coats the back of spoon. Strain the mixture into the tart casings. Bake at 150 deg C for half an hour, or until the custard mixture is firm.