Preheat the oven to 170℃ (fan-forced) or 180℃ (top/bottom heat mode).

Line the baking pan with parchment paper or grease it with butter and sprinkle with flour/breadcrumbs.

Squeeze the juice from the orange and grate its zest.

In a bowl, mix together the wet ingredients for the dough and orange zest.

In a larger bowl, mix the dry ingredients for the dough.

Pour the wet ingredients into the dry and mix - the dough will be thick.

If the dough is too thick and doesn't combine well, add a little more juice or milk.

Transfer the crumble ingredients to a bowl.

Crumble them together - with your fingers or a fork, until they combine into a lumpy mixture.

Transfer the orange dough to the prepared mold.

Sprinkle with orange crumble on top.

Place in a preheated oven and bake for about 30-40 minutes - until a dry skewer comes out clean.