Tuna with Mashed Potato Purée

In a large pot, bring the tuna, milk, and half the salt to a boil over high heat

When it comes to a simmer, reduce the heat, partially cover the pot, and let it cook for about 10 minutes

Drain the tuna and reserve 2 cups of the liquid

In another large pot, sauté the onion in low heat with olive oil, thyme, remaining salt, and black pepper until caramelized, without burning

Add the reserved milk, stir, and cook until the liquid evaporates, leaving the onion still moist (about 10 minutes)

Remove the thyme sprigs. Reserve

Prepare the mayonnaise: in a blender, beat the egg, yolk, salt, and lemon juice

With the blender running, slowly add the oil and olive oil in a thin stream until thickened. Reserve

Preheat the oven to 200°C (hot)

Prepare the purée: in a medium pot, melt the butter over medium heat

Add the remaining ingredients and mix until the purée is smooth

Cover and reserve

Place tuna chunks in a refrigerator, add the onion, and mix

Top with reserved mayonnaise

Arrange spoonfuls of purée on top of the mayonnaise, along the edges of the refrigerator, decoratively

Bake in the preheated oven until golden brown (about 20 minutes)

Serve immediately

850 calories per serving.