Once again, I resorted to the trusty Edmonds cookbook for my recipe (I would love other custard square recipes, though - feel free to email me at email@example.com if you have one you think I should try!). The only problem with that (to me) is that Edmonds is a brand of baking products, and since they make custard powder pretty much everything in the cookbook which uses custard uses their custard powder. Oh well - gotta try everything once (or maybe two or three times, I have made these before, a looong time ago).
The first step is to bake some pastry. I really can't be bothered with making my own flaky pastry - waaaaaaaaaaay too much effort for average results - and really like the Edmonds butter puff pastry you can get frozen at the supermarket (this whole post is basically turning into a big promo for Edmonds, huh?). Because the pastry is supposed to be flat you have to stab it many times with a fork, as evidenced above, so the air can escape and it cooks to crispy, but flat, perfection. Keep a clean teatowel on hand and gently press any air which does get in out as soon as the pastry comes out of the oven.
The custard lifecycle
The custard was pretty straightforward - though do remember to stir it continually - the biggest problem I had was the rather oblique instruction to "Cook until mixture is very thick." Well, sure, but what is very thick? Certainly well past the normal custard measure of 'coats the back of a spoon'. We'll go with 'gloopy and a bit wobbly', shall we?
I baked the pastry and made the custard late last night, then left the custard to chill overnight and assembled it all this morning before work. I used the mixer to smooth out the set custard (the second-to-last photo above shows you the roughed up custard before I did this) and then (my little addition) whipped some cream and beat it through the custard. This gave me a nice, smooth (but still suitably viscous) custard with a little extra decadence-factor.
Assembling the thing was easier than I expected; the trick is having thick enough custard. I baked four sheets of pastry but only needed three for the amount of custard I had (a double recipe). I lined up tops and bottoms and made sure the join lined up, then spread the custard over the bottom pieces and put the others on top. Easy peasy. Then I made a simple butter/icing sugar icing with a bit of lemon juice, and sprinkled coconut over the top. To transport it to work I cut it into slabs and put it into two large containers, then let it chill in the fridge there until lunchtime, when I cut it up for my colleagues to enjoy. My best custard square cutting trick; tip the bit you are trying to cut on its side and cut through that way - stops the filling squishing out the sides!
Custard Squares (adapted from Edmonds cookbook)
2 sheets ready rolled puff pastry (you will likely only need 1.5 but the geometry is easier if you trim 2!)
4 Tbsp custard powder
3 Tbsp icing sugar
2 cups milk
1 egg, beaten
1 tsp vanilla paste
Preheat oven to 220 C. Prick the pastry all over with a fork and bake for 8-10 minutes, until golden.
In a saucepan, mix custard powder, icing sugar, and 1/4 cup milk to a smooth paste. Mix in the remaining ingredients and cook over a medium heat until very thick and viscous (a bit wobbly!). Stir in vanilla paste. Press plastic wrap onto the surface of the custard and cool.
Spread custard over one of the pastry squares. Once you have spread it to the desired thickness you can trim if required - trim a matching piece off the pastry top, too. Place the second piece of pastry on top of the custard.
1 cup icing sugar (approx)
lemon juice (or other flavouring of your choice)
Melt butter in a small bowl, then mix in icing sugar. Add water gradually until you get a thick pouring/spreading consistency. Spread over the top layer of pastry then sprinkle with coconut. Chill.
Cut into pieces to serve - best eaten within 24 hours.
So how was it? I was pretty pleased with the assembly - I have memories of custard oozing everywhere and it being more a custard sandwich than a slice, so I was pretty happy to produce something with height. I am not, as I mentioned earlier, a big fan of custard powder, and I felt the custard wasn't fantastic - next time I'll try a from scratch custard - and I would have liked to have had lemon zest for the icing. I gave them 6/10 (Mr Cake thinks 6.5/10), so not too shabby - but room for improvement. ;-)