For the sauce, in a small bowl, whisk the miso, nutritional yeast, and broth until well-combined. Set aside. In a medium nonstick skillet, melt the butter over medium heat. Once the butter is foamy, lower the heat to medium-low, add the herbs and red pepper flakes, then cook for one to two minutes, until sizzling and fragrant. Carefully stir in the wine, then simmer for one minute. Stir in the milk, bring the sauce to a gentle simmer again, then cook for two minutes, reducing slightly. Stir in the miso mixture and lemon juice, cooking over low heat for one minute to warm through.