In a large bowl, rub butter into flour until mixture resembles coarse breadcrumbs. Add sugar, eggs, sour cream and 1 tablespoon ice water, and stir gently until mixture starts to come together.

Brush a baking dish with butter and scatter over the Demerara sugar. Set oven to 180 degrees. Whisk the eggs with the sugar until pale and creamy. Sieve in the sugar and add the milk. Whisk to a ...