Yes. This is the Royal Wedding Cake that Prince William chose. The one that was not the fruitcake. The one that was not decorated in white icing. The one that is super easy to make, and as rich as a candy bar.
They say that British foodies were appalled at the low cuisine profile of this no-bake digestive biscuit cake, but it cannot be denied that everyone likes this dessert. I mean, who doesn't like candy bars? And I'm sure the royal bakers did not complain that at least one thing about this wedding was simple, even though they did dress it up elegantly (scroll all the way down this article to view the royal chocolate cake).
You can find digestive biscuits (McVitie's brand or otherwise) in the States easily enough; CostPlus World Market has a few brands, and I even found them at a local Persian market. I made the cake with plain biscuits, since the cake was so chocolaty I thought it would be good to add some non-chocolate crunch, but you may use the chocolate biscuits if you want to be completely true to Prince William. And no, they don't actually affect your digestion; don't be driven away by the unappealing name of these cookies, since they are not so different from graham crackers.
I decorated mine with some yummy Belgian chocolate caramel crisps and some more crumbled biscuits, but you could go without decoration, or create a riff of your own. Regardless, it will taste great, and serve a LOT of people; few people can eat more than a small sliver of the dense chocolate.
Royal Wedding Cake: Chocolate Digestive Biscuit Cake
Taken from seriouseats.com
800 g bittersweet chocolate (chips work)*
1 1/4 sticks unsalted butter, cut into 1 inch pieces
2/3 C corn syrup (or golden syrup, if you've got it)
275 g digestive biscuits
Line a 9 or 10 inch springform pan with parchment paper on the bottom. You may make a tiered cake with one 4.5 inch and one 6 inch springform pan. This cake would be difficult to remove from a regular cake pan, and the sides come out shiny and smooth, so you don't want the parchment paper to creep up the sides. Break biscuits into bits 1/4 inch or so, as pictured below (for fun, use your bare hands on the biscuits!), and set aside in a large mixing bowl.
In a double boiler, combine the corn syrup (or golden syrup) and butter, stirring until butter is melted. Add the chocolate and stir until all is melted.
Combine and mold:
Pour melted chocolate mixture over the biscuit bits and stir until well combined. Pour mixture into prepared pan and smooth the top with a spatula.
Let cake set in the refrigerator until the chocolate is hard and shiny, at least four hours. Unmold and cut with a sharp knife in very thin pieces when serving.
*Gram amounts can be estimated by the weight listed on the package you purchase if you don't have a kitchen scale. This is not a fussy recipe, so don't worry about being accurate to the gram.