Diavolo pasta pie

Ingrediënten

• 60ml olive oil, plus extra for greasing
• 40g unsalted butter
• 2 fennel bulbs, trimmed, halved and thinly sliced (400g)
• 2 tsp fennel seeds, lightly crushed
• 3 garlic cloves, thinly sliced
• 1 tsp caster sugar
• 4 tbsp rose harissa
• 200g jarred roasted red peppers, drained and thinly sliced
• 100g pitted kalamata olives
• 350g tomato passata
• 350g zitoni (or bucatini) pasta
• 125g buffalo mozzarella, torn into bite-size pieces
• 10g basil leaves
• Fine sea salt