Preheat the oven to 400º F/ 200ºC.

Scrub the potatoes, pierce a few times with a fork, and rub with olive oil. Place in a baking tray and bake for 30 to 45 minutes.

In the meantime, season the smoked salmon with lemon juice and set aside to marinate.

Wash the swiss chard, separate the stalks from the leaves and chop them, keeping them separated.

In a pan, heat oil over medium-high heat. Add stalks, and cook until beginning to soften, about 4 minutes. Add leaves, reduce heat to medium-low, and cook until tender, 6 to 10 minutes, stirring occasionally. Season with salt and pepper.

When potatoes are baked (they should be soft when you prick with a knife), remove them from the oven and carefully slice in half. Gently purée the insides with a fork and top with the sautéed chard and the marinated smoked salmon.