Peel the pumpkin and potatoes. Cut into small cubes and put all in a non stick baking pan. Pour 15 ml of olive oil and stir with a wooden spoon.
Bake in the oven at 350°F for about 35/40 minutes until golden and crispy. Peel the Jerusalem artichokes and cut into small pieces. Pour 15 ml of extra virgin olive oil in a pan and add a clove of garlic.
When garlic is golden add the Jerusalem artichokes. Sauté for 5 minutes, then add 500 ml of vegetable stock. Let simmer for about 10 minutes. Turn off the heat. With an immersion mixer blend the Jerusalem artichoke until creamy.
Add a little fresh chopped parsley and pour into cups. With the immersion mixer blend potatoes and roasted pumpkin with the remaining vegetable broth until creamy.
Pour this cream into cups. Decorate each cup with chopped roasted pistachios and serve.