SPRING was stalling. We’d been enticed out, like the daffodils, by the warm sunshine only for grey clouds to gather and nasty, cold splodges of sleet to fall from them. We sought sanctuary in the castle, and took tea in the library, surrounded by books and busts, with an unknown 16th Century astronomer looking down on us.

The library at Auckland Castle is a sumptuous setting for a tearoom. Loose leaf tea is poured through a strainer from a china pot, sugar lumps are deployed by tongs, and the food is served on artfully miss-matching plates from the back of someone’s grandma’s cupboard.

The weather was not so sophisticated, and to prevent walkers from Auckland Park trampling mud into the library’s pink carpet, overshoes were provided at the door.

The menu was as rich as the carpet, and was chalked on a board by the door. There were five main fancy dishes, plus a soup, and an assortment of homemade scones and cakes – it felt like the restaurant at the Bowes Museum in Barnard Castle, but probably a couple of pounds cheaper.

To me, several items on the menu looked deeply intriguing and deserved study. After much thought, I decided against the bacon and duck egg pie with pease pudding, castle chutney and beetroot salad (£5.50) because I regard beetroot, like rhubarb, as being unnaturally red. Instead, I chose the North Sea Fish Cassoulet with garlic and cheese crust (£6.95).

To grandma, it all looked too much. “I don’t know if I like Jerusalem Artichoke,” she said, dismissing the adventurous-sounding soup, and plumbing for a sensible fruit scone with preserve and cream (£2.30). It came warm as if fresh from the oven, accompanied by the castle’s own jam. “It’s red and fruity and very good,” she said. Grandma is many things, but food critic is not one of them.

Young Theo, who also prefers simple food, was catered for by the children’s meal box which, for £4.50, included a cheese sandwich on homemade white bread, a bag of mini-cheddars, a drink, a box of raisins and a large custard cream biscuit.

The cassoulet was excellent, certainly much easier to digest than some of the ancient books on the shelves beside us: The Gnostic Heresies by Mansell, Cities and Cemeteries of Etruria (volumes one and two), The Royal Commission and the Ornaments Rubric by Malcolm MacDowall, and Studies of Arianism by HM Gwatkin.

Google tells me that Arianism “chiefly refers to the character and chronology of the reaction which followed the council of Nicæa”. My tastebuds told me that the character, and possibly the chronology, of the cassoulet was that of a superb steaming fish stew. It had chunks of white fish in a delicious tomato and onion sauce plus butter beans and potato, and possibly a mussel. It was topped by a slice of homemade white bread smothered with melted cheese and herbs.

Having completed our studies of Arianism, Theo and I investigated the cakes (£1.50-£2.60). There was a carrot cake, a ginger and lime cake, and a bakewell biscuit, but we decided to share the white chocolate cheesecake with, ahem, rhubarb compote. It was a huge, sturdy slice on a biscuit base, and although I would not have guessed there was any chocolate involved, the compote really lifted the dish. Despite my prejudices, it was slightly sweet and moist - rather than stringy and strident as I had feared – and it complemented the sturdiness of the cheesecake nicely.

Having been challenged by the rhubarb rubric, I decided to return to Auckland Castle a week later to take on the beetroot heresies – all in the name of research.

This time I was accompanied by my wife, Petra, who was prepared to tackle the adventurous-sounding soup. This time, we dined with a bust of Bishop Edward Maltby looking down on us, and the soup was chestnut mushroom with bacon jam (£4.50). Petra wasn’t sure what the bacon jam was up to – there might have been little bits at the bottom – but the soup itself was really good, a great depth of flavour, and she struggled to think if she had ever come across a better mushroom soup.

The bacon and duck egg pie was really a large, upmarket slice of gala pie. The porky meat was pressed like a terrine between pastry, and was perhaps a degree too cold. On top sat a semi-runny duck egg. It was very nice and was enlivened by the accompaniments: a green salad with crunchy crutons, a fruity chutney, a smooth and mild pease pudding and sharp, explosive cubes of red beetroot. Almost every mouthful was different – it was as good as the cassoulet, and there was a purpose to the beetroot.

With cakes and cups of tea, the visits came to a little more than £20 each. The only drawbacks were logistical ones. The toilets are an outside trip away in the main castle, which is inconvenient if you’ve made yourself comfy in your overshoes, and the parking – unless you strike it lucky in the market place – is a stroll away in North Bondgate which is uncomfortable if the weather is throwing cold splodges of sleet at you.

The tearoom itself, though, is a grand treat with evening meals due to start in the near future.