This week I'll tell you a tale of Italian food and Italians. It began when my friend Sergio Regoli phoned me from Rome to say he was coming to visit for a couple of days. Now if you ever have Italians to visit, you'll know that pleasing their palates is not an easy task. They're hard to please, they mutter darkly when presented with unfamiliar foods, they complain readily if a dish is not cooked as it's supposed to be. They're difficult.

I knew I'd have to entertain him a few times and I already had oysters and Guinness planned in the Roundwood Inn, but a meal in Dublin was going to be trickier. Yes, there are places where Italian cooking can be got, but a place that caters for fussy Roman gastronomes is a harder place to find. I've long maintained that there are two wonderful Italian chefs in Ireland, both called Roberto. Roberto Pons is now in Wexford town in La Dolce Vita, but that was a longer drive than I was prepared to contemplate. The other Roberto, Roberto Morsiani, has moved several times since he left Da Roberto in Blackrock, and even spent some time not cooking at all. So when I heard that he was back in business in the same week that I knew Sergio was coming, it was clear that these two events would have to converge.

Roberto Morsiani has had a long career in catering, altogether he has had fourteen restaurants in Bologna, which is undoubtedly the epicentre of Italian gastronomy. He even got a Michelin star in one of them, so trust me, this man can cook. He came to Ireland a few years ago with his Irish wife Janet, and since then he's been looking for a business plan that didn't involve working late at night. He's found it, I think, in 'Janet's Coffee House and Deli' in Dun Laoghaire's Georges Street, which he and Janet now run. True to his plan, it's open from seven o'clock in the morning until five in the evening, when it closes.

Janet's Coffee House is simply laid out: there's a counter on your right as you enter where you can buy a selection of pannini and jars of Italian goodies like rocket pesto, various spreads for making your own bruschetta and roasted vegetables under oil. It's worth mentioning that the rolls for the pannini are exactly the same as you'd get in Italy, because Roberto makes them himself. There's a few tables opposite the counter, and then there's a mezzanine which is used as an overflow.

The menu concentrates on snacks like various breakfasts, cold platters and salads, with the novel twist that you can order anything at any time of day, including the breakfasts. But a full Irish breakfast wasn't what I had in mind for Sergio, what I wanted was Italian food. We got there about four o'clock in the afternoon, so as meal times go it was neither fish nor fowl. We decided in the end to share a mixed Italian platter between us, which was essentially an antipasto on a plate, including salami, mortadella, cured ham, mozzarella and vegetables, both pickled and under oil. This, with the delicious bread on the table, disappeared really quickly between us.

There are no main courses as such on this coffee house menu, but there are plenty of pasta dishes. Sergio and I got into a long conversation about the Amatriciana sauce - whether or not it should include chopped onions, or even whether, as some new-age Italian foodistas maintain, it should be made without tomatoes. We both agreed that this Roman dish was best made with both tomatoes and onions. Sergio decided to order a plateful of penne all'Amatriciana to see what Roberto did with it, and I chose the spaghetti carbonara, which I thought I would compare to my own. What's remarkable about the pasta dishes in Janet's Coffee House is the price. A plate of pasta ranges from €4.80 for a simple tomato sauce to €7.90 for tagliatelle Bolognese. Most of the pasta dishes are around €7, which in my experience is about half what you pay elsewhere for the same dish.

I'll re-phrase that. It won't be the same dish. It may have the same name, but that'll be where the similarities end. If you want to know what a pasta with an arrabbiata sauce should taste like, or an Amatriciana, a Bolognese, a Pugliese, or a Zingara sauce, then go to Janet's and taste Roberto's version. It's not some pale ersatz half-executed version of an Italian dish, it is the Italian dish, made exactly and precisely as you'd get it in a good restaurant in Italy. Sergio was ecstatic over his Amatriciana, grudgingly admitting it was better than his own, while I had to make the same admission when it came to my carbonara.

Apart from the fact that a plate of pasta is good value here, it serves as a touchstone - a benchmark against which others should be compared. You may have got to like a version of 'spag bol' that some restaurant makes, but if you want to know how it's made by a real chef from Bologna, then as far as I know, there's only one place in Dublin to find out, and that's here.

For the moment there's no wine or beer available, but then again it is a coffee house. We had water and Coca Cola with our late lunch and since I still had to drive to Wicklow that was probably as well. Obviously we had to finish our lunch with a coffee in a coffee house, so we did. And yes, even the espressos were good. A bill for less than €30 was an added bonus.