Crying tiger butter

Name: Crying tiger butter
Prep time: 15 min
Total time: 15 min
Yield: 6
Cuisine: Thai
Ingredients: small piece ginger, finely grated; 3 cloves garlic, finely grated; 2 bird's eye chillies, finely diced; 100g (3.5 oz) softened butter; ½ tbsp fish sauce; zest of 1 lime; small handful coriander, finely sliced; small pinch salt