Easy tinned tomato risotto

Name: Easy tinned tomato risotto
Prep time: 30 min
Cook time: 1 h
Total time: 1 h 30 min
Cuisine: European, Italian, Mediterranean
Ingredients: 2 tbsp olive oil, plus extra to serve; 2 medium onions, finely chopped; 2 garlic cloves, crushed; ½ tsp dried mixed herbs or dried oregano, plus extra to garnish; 400g tin chopped tomatoes; 300g/10½oz risotto rice; 1 vegetable or chicken stock cube; 900ml/1½ pint freshly boiled water; 40g/1½oz cheddar, finely grated; salt and ground black pepper