The caterer, set up by Simon Elliot and Andrea Walwyn, will run a café bar at the castle and museum, which is a brand new multi-million pound facility opening 18 May.
Gold & Brown will also look after hospitality and banqueting for events at the separate Park Green Café at the site, which will create ten jobs.
The deal, which runs for five years, is estimated to be worth a combined turnover of £3.25m during the full term.
The caterer, which operates predominately in the profit sector running contracts on a concession basis at visitor and leisure destinations, will also launch services at arts and community centre ARC in Stockton on Tees near Middlesbrough on 1 April.
Turnover at the ARC site is estimated at £840,000 over the three-year contract term. Gold & Brown will run a café bar (branded Caffétessen) on the ground floor, evening restaurant on the third floor, as well as supplying refreshments and looking after a reading area and corporate events space at the site.
Annabel Turpin, director of ARC, said: "We want to make ARC the place to go in Stockton for both entertainment and for food and working with Gold & Brown will help us combine the two.
"At the same time, we are showing our support for the principles of food miles, ethical business practices and fair-trade."
The caterer launched its first contract at the Academy Health Club in Harrogate, North Yorkshire, last October.
In November Gold & Brown was the inaugural CaterersearchFoodservice Website Web Awards winner.
By Chris Druce
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