Prawn and Pineapple Tom Yum with Rice Noodles

Ingredients

• 2 vine-ripened tomatoes, coarsely chopped
• 20 gm each ginger and galangal, coarsely chopped
• 6 kaffir lime leaves, coarsely torn, plus extra, to serve
• 4 garlic cloves, coarsely chopped
• 4 coriander roots, scrubbed plus leaves, to serve
• 3 red shallots, coarsely chopped
• 4 red birdseye chillies, coarsely chopped, plus extra, sliced, to serve
• 2 lemongrass stalks (white part only), thinly sliced
• 150 gm pineapple, coarsely chopped
• 1 1/4 litres hot chicken or fish stock (5 cups)
• 100 gm thin dried rice noodles
• 16 medium uncooked prawns, peeled and cleaned
• 100 gm cherry tomatoes, halved
• 90 ml fish sauce, or to taste
• Juice of 3 limes, or to taste
• 1 tbsp coconut sugar (see note)