2. Place potatoes in a pot of cold water with olive oil, basil, rosemary, and cayenne. Bring to a simmer and cook for approximately 30 minutes, or until you can insert a knife easily into a potato.
3. Drain potatoes and pass them through a ricer.
4. Add soymilk, salt, and pepper, and mash with a potato masher.
FOR THE SAUCE: 1. In a saucepan, heat oil on low.
2. Cook garlic and onion until lightly brown. Add mushrooms and cook on low for 15 minutes.