Preheat the oven to 180°C.
Grease and line a 24cm loose-bottomed cake tin with greaseproof paper.
Bring milk, vanilla, lemon zest, and sugar to a boil in a large saucepan.
Add rice and simmer for 20–25 minutes until al dente and creamy.
Remove from heat, allow to cool, and discard vanilla pod and lemon zest.
Whisk egg yolks and liqueur in a bowl until creamy.
Whisk egg whites in a separate bowl until stiff peaks form.
Stir the egg yolk mixture into the cooled rice.
Fold in the egg whites, raisins, and orange zest.
Pour into the tin and bake for one hour.