Heat the olive oil, add the shallot. Cook the shallot until it’s softened, then add the garlic. Cook until fragrant, 1 minute. Add the bacon fat, and allow it to melt. Add the diced stems. Stir and cook for 2 minutes, and then add the chiffonade leaves. Stir and cook for 2 minutes. Add pepper & salt, then add the cream. Stir and continue to cook for 3-4 minutes. Taste. Add more salt and pepper if needed. Serve immediately.