Do you remember school dinners? Do you remember your favourites? Or, perhaps, like me, your least favourites were more memorable?

I, for one, have never been able to eat jam, or most gelatinous things like honey or jelly, after being force-fed it in my first week of infants school. For a whole hour I inched my way through a bowl of custard with jam, banned from leaving the table to go out into the playground by two monsters who said I had to finish it despite hating the stuff. The monsters were, of course, 7-year-old dinner monitors. It is one of my earliest memories and not one I cherish.

I also have a bit of an aversion to lemon meringue pie which most of my schoolmates loved. That combination of claggy meringue and over-sweet lemonyness has never won me over, yet I love lemon. So when I saw what sounded like a perfect lemon shortbread bar in Deb Perelman’s The Smitten Kitchen Cookbook I was won over by the simplicity of the recipe but wary of the result. It sounded a bit too close to lemon meringue pie, but with shortbread. And inverted. Okay, not that close but you know what I mean. However, the recipe was incredibly simple and I had a surfeit of lemons so, in the interests of research and wanting something to cheer me up everyday around 4pm, I went for it. Worse case scenario I could take them to the office and give them away.

Reader, it was the office that was disappointed not me. These are gorgeous, lovely and lemony but not over-sweet, and so easy: fast, straightforward and very very light on equipment. And there’s hardly any shopping: you probably have most of the ingredients at home already. I have had two every day this week, tucked into the afternoon like a little bit of sunshine with a cup of tea, and I have a feeling I shall be making more this weekend. You won’t need any persuasion to finish these off.

Smitten Kitchen’s Lemon Bars (adapted from The Smitten Kitchen Cookbook)
(NB Having made these a few times now, I can safely say that the balance between the sharpness of the lemons and the sweetness of the sugar is not always the easiest to get right. They will always taste delicious but, depending on your preference, you can lose up to 65g of sugar from the filling without it mattering. So, unlike many a cake recipe, this one can bear a tweak or two.)

Cupboard (or things you may already have)
plain flour, 125g
sugar, 330g
salt, ½ tsp
unsalted butter, 230g, plus a little for greasing the tin
eggs, 4

Shopping list
lemon, preferably unwaxed
cornflour, 15g

How to
1. Preheat the oven to 180°C/160°C/gas 4. Cut two lengths of baking parchment longer/wider than an 8-inch square baking tin. Press one into the tin in one direction, the other in the opposite direction (you are making a sling to lift the bars when they are done) then grease the paper with some butter.
2. First make the shortbread crust. Put the flour, 65g of the sugar and ¼ teaspoon salt into a food processor (or in my case blender) and mix together. Dice up 115g butter, add to the flour then mix again, on the pulse setting if you have one (I don’t) until you have what is, essentially, a crumble topping: as Perelman very helpfully points out it will look powdery but if you squeeze it between your fingers the powder will stick together.
3. Press the shortbread mixture into the tin. I did this first with the back of a spoon and then with my fist which was marvellously satisfying. Prick all over with a fork and bake for about 20 mins or until just browned. Remove from the oven but leave the oven on.
4. Cut the lemon in half and, though this may sound odd, check how thick the pith is (try saying that drunk). Apparently, if it is more than ¼″-thick, it will lend too much bitterness to the bars, so in that case you have to be fiddly: remove the skin, and pith evidently, from half the lemon but leave the other half intact. Otherwise, if nice and thin, go straight to step 5.
5. Slice the lemon halves thinly, remove any seeds, then put all the lemon (bar anything you remove in step 4) into your food processor/blender, add the remaining sugar (so 265g) and blend until completely puréed (a few minutes).
6. Dice the butter, add it to the lemon purée and blend again until completely smooth.
7. Finally, add the eggs, the remaining ¼ teaspoon salt and cornstarch and blend/pulse once more until completely combined. You may need to stop the machine and give it all a stir with a spatula at some point in this process.
8. Tip the mixture onto the shortbread base and bake for about 35-40 minutes until set and golden. It can wobble a little but not look like it’s really liquid.
9. Leave to cool on a rack then, when cold, use the paper to lift the bars out of the pan and divide into squares.