She’s been here before, the girl with the curtain of shining red hair. “The lemonade that they do here is delicious,” she tells her dad as he settles at an outside table and scans the perimeter to see if he can let her toddler brother go free-range.

We’re sitting in a new garden at an old place. Frondy grasses and cottage garden flowers grow around a manicured carpet of lawn. It turns out they don’t have lemonade today but in a room behind us two great things have come together.

The Mess Cafe at Richmond Barracks in Inchicore is a beautiful room in the restored classrooms of the old barracks. There are high ceilings, arched sash windows and the kind of original glass and timber partitions for which hipster designers would sell their grandmothers.

The original mess clock hangs on the wall with a plaque underneath thanking the donor and wondering how many hungry eyes stared at it in the run-up to mealtimes.

There's a large Irish Press photograph of young men in uniform around a long table groaning with spud-laden plates of food, bunches of flowers and bottles of porter. They grin out from their sepia dinner at a bright white room filled now almost entirely with women.

It’s a sad fact that Irish museum cafe ambitions rarely stretch past keeping the cellophane-wrapped muffins in date. Yet no one is blowing a bugle about the Mess Cafe. My hunch is that it’s only 1916 buffs, the community groups who meet here and their friends who know about it. There is plenty of parking (bike and car) out front beside the green. Apart from a small chalkboard at the entrance there’s little sign that there is food to be had here, much less good food.

The second great thing about the Mess Cafe is the people running it. It’s the Green Kitchen, a social enterprise started in a former butchers’ shop in Walkinstown to train people with learning difficulties in hospitality, kitchen and horticulture skills.

They grow some of the vegetables in a polytunnel out the back of the Walkinstown Green Kitchen. They have a second branch in the Rediscovery Centre in Ballymun. And they’re here, in this historical place, helping people find better futures.

The menu is simple. Everything is cooked from scratch so food can take a while. On my first visit, this is fine. It’s no hardship to soak up the sun waiting for a goat’s cheese and tomato tart, a circle of flaky pastry topped with the kind of ingredients you might find in your own fridge (with the lovely added flourish of candied walnuts) all finished with fresh leaves. There’s a crumbly scone and good coffee to follow.

I’m back the next day with a friend, and the place has filled up with more men this time. Again the food is unfussy lunch staples. They charge little more than sandwich bar prices but food is made freshly from scratch.

There’s an avocado and feta wrap, light and zingy cubes of cheese with softly ripe avocado, spinach and a lemon mayonnaise. Baby potatoes are roasted in their skins to make it a proper filling plate (for €7.50).

I get the baked salmon salad. The fish is a little overcooked but chunky enough to have plenty of juiciness under the crusted outside. It comes with a quinoa salad that manages to make quinoa taste good by teaming it with butter, lemon and flaked almonds. There are sweet green spears of asparagus on top (sadly not grown in their kitchen garden – you need a lot of space for asparagus). It’s a hearty healthy lunch for a tenner.

A slice of apple tart (more pie than tart) is fine, outshone by an individual banoffee pie with spoon sticking caramel topped with beige chocolate sprinkled butter cream.

Visitors come in waves and then the place fills and empties again quickly. The Mess is only open weekdays, according to the website. They need more tables outside and probably a few more staff for when word spreads. Weekend openings would bring a whole new crowd. Dublin 8 is coming down with trendy cafes. But there’s a combination of heart and history here that’s really very special.

• The Mess Cafe, Richmond Barracks, Inchicore, Dublin 8

Verdict: 8/10. Troops, form an orderly queue for a great lunch.
Lunch for two with two coffees and two desserts came to €28.75
Music: Nice
Facilities: Fine
Wheelchair access: Yes
Food provenance: Limited but some ingredients come from their garden
Vegetarian options: Good

Opportunity Knox

We hit what felt like lunch rush hour in the lovely cafe Knox in Sligo recently even though it was nearly 3pm on a Sunday afternoon. Painted concrete floors, galvanised steel and wood chairs and tables made from varnished scaffolding timbers tick all the common decor themes.

But Knox, named after the original street name, was more than the sum of its hipster tropes. They serve great fast food staples made with good ingredients. The burger was luscious beef topped with smoked bacon and good cheese on brioche. A falafel plate was a filling mix of nutty chickpea falafel with house-made flatbread and good fresh salad.

And they serve a 50 cent “baby chino” of frothy milk with a a sprinkling of chocolate for those young people who like to ape their parents’ coffee habit.

• Knox, 32 O'Connell Street, Sligo, 071-9141575. Lunch for five came to €46.50