Tom yum soup

Name: Tom yum soup
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Cuisine: Asian, Thai
Ingredients: 500g medium green prawns; 1-2 medium red chillies,(see note) plus extra, thinly sliced, to serve; 36.80 gm vegetable oil; 3cm piece galangal,(see note) thinly sliced; 1 stalk lemongrass, bruised, cut into 5cm lengths; 6 makrut lime leaves; 60ml (1/4 cup) fish sauce, plus extra, to taste; 125ml (1/2 cup) lime juice, plus extra, to taste; 10.00 gm caster sugar; 100g button mushrooms, quartered; 100g cherry tomatoes, halved; 40.00 ml roughly chopped coriander, plus extra sprigs, to serve