3.Meanwhile, heat oil in 2-litre (8-cup) paella pan or ovenproof deep frying pan; cook onion, stirring, until soft. Add garlic; cook, stirring, until fragrant.
4.Add rice; stir to coat in onion mixture. Add wine; simmer, uncovered, until liquid is absorbed. Add 3 cups (750ml) of hot stock; season.
5.Bake, uncovered, 15 minutes. Stir in marinara mix and remaining hot stock. Bake, uncovered, about 25 minutes, stirring halfway through cooking time, or until rice is tender. Stir in rocket and butter.