Basic Potage from Soup: A Way of Life by Barbara Kafka

Ingredients

• 2 tablespoons (30 g) unsalted butter, optional
• Freshly ground black pepper, to taste
• Kosher salt, to taste
• 6 to 8 ounces (180 to 225 g) onion, leek, shallot, or garlic, or a mixture, cut into ½-inch (1-cm) dice
• 3 to 4 cups (750 ml to 1 l) stock or water
• Cut-up vegetables, per list below
• ¾ pound (360 g) mashing potatoes, peeled and cut into chunks