Halve the tomatoes and scoop out the seeds. Divide the tomato paste among the tomato halves and spread around inside of the skin. Place on a baking sheet and cook in the preheated oven at 400°f for 12-15 minutes. Leave to cool slightly.

Meanwhile, make the mayonnaise. In a food processor, blend the egg yolks and lemon juice with the lemon rind until smooth. Once mixed and the motor still running, slowly add olive oil. Stop the processor as soon as the mayonnaise has thickened. Alternatively use a hand whisk, beating the mixture continuously until it thickens. Add the tuna and capers to the mayonnaise and season.

Spoon the tuna mayonnaise into tomato shells and garnish with sun-dried tomato strips and basil leaves. Return to the oven for a few minutes or serve chilled.

COOK'S TIP:If you prefer the tomatoes firmer and easier to handle, do not roast them. Instead, cut side down on absorbent paper towels, scoop out the seeds, drain for one hour and fill with the mayonnaise mixture. You can also substitute ready-made mayonnaise; just ensure the lemon rind is stirred in.