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ABC News' Nicholas Schifrin reports:

Kate Middleton's sister, Pippa Middleton, is defending her party planning book, "Celebrate" against critics who have called the book too "basic."

The sister of the Duchess of Cambridge is fighting back in an article in the Sunday Telegraph by arguing she wanted to produce something simple.

"I wanted to produce something that was achievable; something that people would have on their shelves for years; something that was not too fussy," Middleton wrote in the article.

She reveals for the first time that she worked in the most working class of establishments - a pub.

"My interest in food really began with a month's cookery course in Frome, Somerset, after my A-levels. I left the course not an incredible cook, alas, but a real enthusiast. Food and cooking is at the core of entertaining, and my passion grew and grew," Middleton wrote.

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Middleton also claims some culinary chops by citing her less traditional dishes such as slow-braised pig's cheeks, muntjac ragu (Chinese deer meat sauce), ox tongue baguettes and pigeon-breast salad.

"She was quite keen to write something that reflected her a little bit more, reflected actually how she's learnt all these tips, where she's learnt them from, something a bit more personal and warm," said Sunday Telegraph Royal Correspondent Roya Nikkhah.

Middleton also revealed that she likes whiskey sours and reportedly plans to write two more books - one about children's parties, another about planning weddings.

"By writing something she takes back control and says, 'this is why I've done it, this is how I learnt to do it, this is why I'm putting it out there.' I don't think she's that fussed about the critics, to be honest," said Nikkhah.