Preheat oven to 350°F (175°C).

Butter the sides of an 8-inch round cake pan.

Line the base with greased parchment paper.

Mix together self-rising flour, brown sugar, cinnamon, allspice, and coriander in a bowl.

Rub the butter into the flour mixture until it resembles coarse bread crumbs.

Spoon half of the crumb mixture into the prepared pan and spread evenly.

In a separate bowl, whisk the egg and nutmeg into the milk.

Add the milk mixture to the remaining flour mixture and stir until just combined (a runny batter will form).

Pour the batter over the crumb layer in the pan.

Bake for 70 minutes, or until golden brown and springy to the touch in the center.

Cool in the tin for a few minutes.

Turn the cake out onto a wire rack and cool completely.