Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).

Peel the peppers and toss with one tablespoon oil. Place onto a Gefen Easy Baking Parchment-lined baking sheet and roast until soft and just browning, approximately 12-15 minutes. Remove from oven and set aside.

Meanwhile, in a large pot, heat three tablespoons oil and add onions. Sauté on low heat until onions are brown. Add the garlic and potatoes and continue to stir until the potatoes begin to soften. Add tomato paste, basil, salt, pepper, and sugar, if desired, and just enough water or vegetable broth to cover the vegetables. Cook until the potatoes are easily pierced with a fork, about 20 minutes.

Add the roasted peppers and blend with an immersion blender.

Place the parsley leaves, walnuts, and garlic into the bowl of a food processor. Process until ground. Slowly add the oil as you continue to process the mixture. Add salt and pepper and process again. A smooth and liquidy mixture should form. If it’s too thick, add some more oil until it’s easily pourable.

When ready to serve, heat soup and drizzle each bowl with a bit of the parsley-walnut oil.