Position a rack in the center of the oven and preheat to 425°F.

Add the sweet potato pieces to an unlined baking sheet and drizzle with olive oil. Season with salt and pepper and mix. Roast the sweet potatoes in the oven for 17-20 minutes, or until soft and golden on the bottoms. Remove and set aside.

Set a large sauté pan over medium heat and add enough oil to coat the entire bottom, about 3 tablespoons worth. Let the oil heat up before frying the sage in batches. To test if your oil is ready, add a sage leaf. If it sizzles when it hits the oil, the oil is ready.

Fry the sage for 1-2 minutes or until they are a shade darker. Remove from the oil and place on a paper towel to drain. Keep the oil in the pan on the stove. Season all the sage with a sprinkle of salt.

Add ¼ cup of the fried sage leaves to a small mortar and pestle. Add in the parsley, garlic, red pepper flakes and juice from one lemon. Drizzle in a tablespoon of olive oil and crush everything into a green sauce, adding more olive oil as needed. You can also do this in a blender or food processor. Season with salt and pepper and set aside.

Bring the pan with the sage-infused oil back to medium heat. Add the onion and cook, stirring occasionally, until it is beginning to soften but not brown, 4-5 minutes. Add ¼ cup of water and stir, allowing the onion to almost melt into softness without gaining any color. Continue stirring occasionally until most of the water has evaporated.

Add the butter beans and swirl to combine. Season with a pinch of salt.

Pour in the wine and stir, bringing the wine to a gentle simmer. Let this cook for 4-5 minutes, stirring so the starchiness of the beans combines with the sage oil and wine to make a rich sauce, another 5-6 minutes.

Crush in the remaining fried sage, reserving a few leaves for topping. Add ¼ teaspoon red pepper flakes. Swirl to combine. Remove the pan from the heat. Taste and season with more salt and pepper as needed.

To serve, scoop the beans onto a plate. Top with ½ cup of roasted sweet potato, a few dots of the green sauce, and a few fried sage leaves. Serve warm.