Step 1In a large skillet, add the olive oil, garlic and shallot. Cook on low heat just until soft. Add the diced potato and squash and stir. While continuing to stir, add the white wine and turn the heat to medium-high. Cook until almost evaporated, about 3 minutes.
Step 2Add one-third of the vegetable stock and continue to stir. When the stock is almost evaporated, about 13 to 15 minutes, add the watermelon radish and another third of vegetable stock and continue to stir. When the liquid in that mixture is almost evaporated, add the peas and the last third of stock, continuing to stir.
Step 3When the liquid in that mixture is almost evaporated, stir in the mascarpone and Parmesan. Season with salt and pepper and stir in the chopped herbs.
Step 1Heat the oven to 225 degrees. Heat the oil in a saute pan. Add the onions, carrots, celery and rosemary. Cook on low heat until softened, about 10 minutes. Transfer the mixture to a roasting pan.
Step 2Place the arctic char on top of the vegetables and cook for 20 minutes. Remove from the oven, remove any vegetables that stick to the fish.
Step 3Season with salt and pepper and serve warm with the vegetable "risotto" on the side.