Firstly, for the budget-conscious among you raising eyebrows at the use of a bottle of the authentic black stuff in a batch of brownies, fear not, for this recipe makes 24 of the little tinkers, and uses a little over half a can at that, so you could stretch to 40ish from a single can if you’ve a crowd to feed. If that doesn’t satisfy you, well, most supermarkets sell an own brand value range can of bitter at around £1 for 4x440ml cans, indeed, I recommend it for my sausage casserole recipe and a few others besides. But, tomorrow being both my birthday and St Patrick’s Day, for me, tonight, it’s got to be the real thing. I’m fussy about very little when it comes to ingredients in cooking, but Guinness makes my non-negotiable list, and I hope for that you, dear readers, will note my half Irish blood and birthday on St Paddy’s day and gently forgive me.

I first came across the idea of Guinness in cooking from the wonderful Nigella, in her book Kitchen, one of my go-to reads for comfort food and seductive words, to relax and unwind, to feel inspired, to find a moment of joy in food at the end of a long day. Her Guinness gingerbread with plums was the inspiration for my own Beery Berry Crumble in my first book, A Girl Called Jack, and both stand up to long cold days and a craving for a little comfort. Today, I mused aloud on Twitter that I was compiling my favourite Irish recipes for St Patrick’s Day, and several readers asked about a Guinness chocolate brownie. Intrigued, I experimented and explored, noted down several recipe variations including my own brownie recipe scrawled into an old black notebook, and here we are: double chocolate Guinness birthday brownies. I hope you love them as much as I do.

Makes 24 small fat rich brownies, at 15p each

250ml Guinness (or other stout, if your budget doesn’t stretch), 71p
200g dark chocolate, 70p
100g milk chocolate, 70p
200g butter, 72p
300g sugar, 27p
3 eggs, 43p
150g flour, 6p
a pinch of salt, <1p

First heat your oven to 180C, and line a small roasting tray with baking paper. If baking paper isn’t the kind of thing you have lying around, give it a good grease with sunflower/vegetable oil to stop your brownies from sticking.

Pour the Guinness into a small saucepan and turn onto a low-medium heat. Perch a mixing bowl on the top – this will act as a bain marie to simultaneously melt the butter and chocolate, and reduce the Guinness. Break up the dark chocolate only, and dice the butter, and pop into the bowl for around 8 minutes to melt, stirring occasionally. Don’t be tempted to crank the heat up, I did and my Guinness bubbled up and made a ghastly sticky mess all over my hob. Patience, it will all work out.

Meanwhile, beat together your eggs and sugar with the pinch of salt until well combined. Gradually add the flour, a quarter at a time, and beat it all in before adding the next batch. You can sift it for a smoother consistency, but a thorough beating with a wooden spoon will do the job just as well, with one less thing to wash up.

When the chocolate and butter are melted and combined, gradually beat those into the mixture. Don’t be tempted to splosh it all in at once, as searing hot chocolate and cold eggs has a lot of potential to go quite wrong… There’s a reason why you don’t generally see ‘chocolate scrambled eggs’ on restaurant menus!

When the melted chocolate and butter are combined with the eggs, flour and sugar, it’s time to add the booze. It should have reduced by half (i.e. there should be 125ml there now, instead of 250ml, as half of it should have evaporated). If it hasn’t, you can either carry on reducing it for a moment now it doesn’t have a bowl of chocolate balancing on top, or just use 125ml of whatever quantity you have left – I can’t imagine it will make a frightfully noticeable difference. Pour a little into the brownie mixture, mix well, and repeat until consistent.

Pour the whole lot into your tray – it will be VERY runny. I had my doubts, slopping it in, that I was going to make anything that remotely resembled a brownie, so if you are pouring brownie soup into your tray with more than a touch of scepticism, you’re doing it exactly right. Break up your milk chocolate and poke it into the brownie soup at random intervals, and put the whole thing on the middle tray of the oven. Close the door, and don’t open it for 40 minutes, no matter how great it smells or how curious you are.

40 minutes later, turn the oven off and remove the brownies, and leave them in a safe place to cool for AT LEAST AN HOUR before slicing them. They carry on cooking while they’re resting, and this is vital. If you’re anything like me you can hover over them watching the top crack and inhaling their brilliant cakey boozy chocolately aroma BUT DON’T TOUCH THEM. If I can do it, so can you.

Then, cut into 24 pieces and demolish one of the corners, just to, you know, check. Leave to cool completely, and pop into an airtight bag or container and store for a few days. If they last that long. Someone’s eaten a third of mine already.

Recipe costs based on current Sainsburys prices as it’s where I shop – correct at the time of blogging and subject to change. Guinness £5/4x440ml cans. Basics dark chocolate 35p/100g. Basics milk chocolate 35p/100g. Basics unsalted butter 90p/250g. Fairtrade granulated sugar 90p/1kg. Mixed weight free range eggs 85p/6. Basics plain flour 55p/1.5kg. Basics table salt 25p/750g.

Jack Monroe. I’m on Twitter and Instagram @MsJackMonroe and on Facebook at http://www.facebook.com/agirlcalledjack