To make harissa mayonnaise, carefully roast the spices in a pan until fragrant. Place in a mortar and finely crush using a pestle. Heat oil in a heavy-based pan and add garlic, salt and capsicum. Sweat, uncovered, over a very low heat for about 2 hours or until soft. Stir often to prevent sticking.

Increase the heat, add palm sugar and cook, stirring, for about 5 minutes until caramelised. The mixture should go a reddish brown. Add fish sauce, roasted spices and chilli powder, then cook, stirring, for 2 minutes. Cool mixture, add lemon juice, then blend until smooth. Whisk the harissa into the mayonnaise and check seasoning.

In a deep fryer or a saucepan, heat some oil to about 180°C. Season the flour with salt and pepper. Toss prawns in seasoned flour, shaking off excess, then deep-fry in batches until pink, crispy and cooked through, about 2-3 minutes. Remove with a slotted spoon and drain on paper towel.

Serve on a platter with lemon wedges and harissa mayonnaise on the side.

Photography by William Meppem. Food styling by Hannah Meppem. Food preparation by Nick Banbury