sultanas and coconut.
Holmes, who once worked under celebrity chefs Gordon Ramsey and Marcus Wareing before becoming an immigration official at the Border Force, U.K.’s version of U.S. Border Patrol, told FoxNews.com that he was resigning to focus on his cake business.
"Food is my passion. It’s always been my dream to set myself up making cakes."
Known as Mr. Cake, Holmes has been building up his side business over the past three years, making handmade cakes out of his home.  His specialty is elaborate, cartoon-like cake toppers.  He said after years of taking small orders for special occasions like wedding cakes, he felt it was time he could do cakes full time.
Holmes said he cooked up his resignation cake idea six months ago, when his wife was still pregnant. "I had to keep it to myself, which was pretty difficult," he said.
What Holmes didn't plan on was his story getting so much media attention.  On Monday, the day Holmes quit, his brother-in-law sent a picture of the cake via Twitter, which went viral and was posted on Reddit.
Holmes said he left his employer on good terms, and even put a special plug for his business on his cake for his former colleagues.
“I wish the organisation and my colleagues the best for the future and I remind you that, if you enjoy this cake, you can order more at www.mrcake.co.uk
Holmes getting inundated with telephone calls, and although some orders have started coming in, none have been for resignation letter cakes.
"This has exceeded all my expectations," he said.