1. Heat 1 tablespoon canola oil in 12-inch nonstick skillet over medium heat until shimmering. Add onion and ¼ teaspoon salt and sauté until lightly browned and translucent, about 7 minutes. Transfer to food processor.
2. In same pan, heat 2 Tbsp. canola oil over medium heat until shimmering. Add mushrooms and ½ teaspoon salt and cook, stirring occasionally, until soft and lightly browned, about 5 minutes. Transfer to food processor.
3. Add eggs, walnuts, and tomato paste to food processor. Process until smooth, wiping down bowl as necessary. Season with salt and pepper. Serve with crackers or matzah.
Want to try the meat version? Get the recipe for chicken-liver terrine here.
Reprinted with permission from JewishBoston.com.