Peel and cut the potatoes in half. In a large skillet, heat olive oil over medium heat. Add the potatoes, cut side down, and cook until golden brown. Add water to cover the potatoes halfway, and season with salt. Cover and simmer for about 20 minutes until tender.

Make the Saffron Aioli

In a bowl, combine the egg yolks, crushed garlic, saffron, and a pinch of salt. Slowly whisk in 1/2 cup of olive oil until emulsified. Adjust seasoning with lemon juice, salt, and pepper.

Prepare the Sauce Vierge

Finely chop the heirloom tomatoes, basil, and parsley. In a small bowl, mix together with lemon juice, olive oil, and season with salt and pepper.

Char the Mackerel

Preheat the grill or grill pan over high heat. Season the mackerel fillets with salt and pepper. Grill for about 3-4 minutes on each side until charred and cooked through.

Plate the Dish

On a plate, place a portion of the potatoes fondantes, top with grilled mackerel, drizzle with saffron aioli, and finish with a spoonful of sauce vierge.