1. Preheat the oven to 375°.
2. Cut the top third of garlic heads off so tops of cloves are exposed. Place heads, unpeeled, in ovenproof dish and drizzle with 1 tablespoon oil. Cover with aluminum foil; bake 30 minutes.
3. Uncover and bake until the garlic cloves are soft and golden brown, another 30–40 minutes. (Make ahead and store in an airtight container in the refrigerator for up to 5 days.)
4. In a food processor, combine the beans, roasted garlic, remaining 3 tablespoons oil, and lemon juice and process until smooth. Add the salt and white pepper. This will keep in an airtight container in the refrigerator for up to 3 days.
5. To serve, transfer to a bowl, garnish with the parsley leaves, and serve with vegetables.