The Serpentine gives plenty to gander at, but is the food at Hyde Park's revamped café strictly for the birds?

I could lie and say I was jogging round Hyde Park when I stopped off for a bite to eat. After all, as I sit in the Serpentine Bar & Kitchen, plenty of sporty types are peeling off the nearby path, where they have been running, shadow-boxing, Rollerblading or practising rugby moves to come into the distinctive low-slung building for juice, a muffin or something more substantial.

The truth is, I drive to one of London's biggest green spaces, park my car and walk the very short distance to the newish eatery on the edge of the Serpentine. I'm not big on exercise, but I love the idea of having supper in the middle of the park with a couple of junior Ms. They want to watch blokes on skates perform stunts, and then menace a few geese, but I'm more in favour of watching the sun go down over the lake with a glass of wine and a plate of food. The 8pm closing time is looming, the sun is edging down and children have a low ordering/delivery threshold when it comes to grub.

The restaurant opened at the beginning of the summer with some fanfare, when café chain Benugo took over the elegant pavilion site from the unloved Dell. It got a stinky review right at the start, but has had a few months to polish up its act.

With zero calories burned on the way in, who was I to order anything other than a salad? There are four punchy-sounding offerings, from warm goat's cheese to rare roast beef, but – of course – I'm feeling piggy. The menu has nothing over £11.50, and apart from three typical "main-course" numbers (stuffed lamb breast, roast chicken, baked sea bass), everything's the kind of substantial snacky stuff which is just right for a bustling, drop-in joint. There's a proper wood-fired oven, too, so pizzas look tempting. On the piggy front, today's roast-meat sandwich is pork belly. What to choose?

The solution is to make everyone order from a different section. The littlest M gets a "plain pizza" – tomato, mozzarella and oregano to you and me (£7.50). Her main reason for her choice is that she can go and watch the chefs make it, while her big brother would rather sit back and have food brought to him. To my surprise, he chooses fish of the day (salt and pepper squid, £9.50) over that meaty sarnie – and that's after he's toyed with the idea of mackerel fillet with gooseberries and home-made sourdough bread... A food critic of the future, perhaps.

My greed is my undoing. The lamb breast stuffed with apricots with new potatoes and garden peas is the least inspired of the three mains and I should have realised that ordering something that requires slow cooking half-an-hour before the chef clocks off means it's likely to have been knocking about a bit. I don't mind room-temperature roast, and the skin is crisp and the meat tender, but it's dull and dry. Nice peas, though.

The squid's a bit of a triumph: generous rolls of griddled flesh, lip-smackingly seasoned and not in the least rubbery. Master M even eats the salad beneath it, because the salty coating has rubbed off on the green stuff. Miss M's pizza, prepared under her watchful eye, is pleasingly bubbled and crisp and only a desire to save some for the geese stops her gobbling the lot.

I get the chance to sit back and survey the room with a glass of serviceable Montepulciano d'Abruzzo at £4.75 – from a no-surprises, plenty-of-classics wine list – while they go out to throw pizza crusts at unsuspecting fowl. It's suitably low-key, but the details are telling. The rustic wooden tables have quirky touches such as condiments in old cake tins, and potted herbs on mismatched floral crockery. The central area with comfy chairs has a battered Scrabble set and books to browse. Teaspoons reside in an old Tate & Lyle syrup tin, while behind the bar, a waitress carefully hand-fills muslin bags with tisanes.

When I order coffee at the bar, the waiter gives a little sigh. He thinks it's a bit slow tonight, but I'm glad. Others have reported that when the kitchen is at full stretch (and it feeds 300), quality slips significantly. So I'd say it's a charming place to go now that summer's ending and the fair-weather joggers and skaters will stop cluttering up the place. The building's chic, the view is wonderful and if all else fails, the chocolate cakes are scrumptious. The geese got none of them.

14/20

Scores: 1-9 stay home and cook, 10-11 needs help, 12 ok, 13 pleasant enough, 14 good, 15 very good, 16 capable of greatness, 17 special, can't wait to go back, 18 highly honourable, 19 unique and memorable, 20 as good as it gets

Serpentine Bar & Kitchen, Serpentine Road, Hyde Park, London W2, tel: 020 7706 8114. Open daily, 8am-8pm. £40 for two, including wine and service

Second helpings: More waterside treats

Riverside

West Bay, Bridport, tel: 01308 422 011

This café, on a little island in the river, has long been one of the best-known restaurants on the south coast, and fish doesn't come any better than the huge range on offer here

El Faro

3 Turnberry Quay, London E14, tel: 020 7987 5511

A hidden gem near Crossharbour DLR; El Faro serves some wonderful and authentic Spanish dishes and has nice waterside tables, too

Frère Jacques

10-12 Riverside Walk, Kingston upon Thames, Surrey KT1, tel: 020 8546 1332

A beautiful location, by Kingston Bridge, and an owner who treats you like his best friend are the hallmarks of this no-nonsense outfit, good for steak frites and classic bistro fare