In a dry skillet over medium heat, toast the almonds until lightly golden. Remove the almonds from the pan and set aside.
Return the skillet medium heat and warm the butter with 1 tablespoon olive oil. Add the onion and saute until translucent, about 5 minutes. Add the lima beans, salt and chicken stock. Bring to a simmer, and cook until the lima beans are heated through and tender, about 5 minutes.
Carefully transfer the mixture to a food processor. Add the mint and puree until a smooth, even consistency is reached. Season with salt, if needed. Transfer the puree to a serving bowl and serve garnished with a drizzle of the remaining olive oil, black pepper, to taste, and the toasted almonds.