Photograph: Jonathan Gregson
Preheat the oven to 220°C, fan 200°C, gas 7. Use a pestle and mortar to grind the anchovies and garlic to a paste, transfer to a bowl, then add the mustard, chopped herbs and green chilli. Gradually drizzle in 6 tablespoons of olive oil, stirring to make a thick sauce, then stir in the cucumber and season to taste.
Brush the hake with olive oil; season. Arrange on a lightly oiled baking tray, toss the tomatoes in a little oil and put in the tin. Roast for 8-10 minutes until cooked through (15-20 minutes for cutlets).
Serve with the salsa verde and lemon wedges to squeeze over.
Get ahead: make the salsa verde up to a few hours ahead, cover and chill.