How to Make It
In a large saucepan of boiling water, cook the potatoes until tender, about 20 minutes. Drain and halve the potatoes.
Meanwhile, in a large nonstick skillet, melt the butter. Add the sage and cook over moderate heat, stirring, for 2 minutes. Pour all but 1 tablespoon of the sage butter into a small bowl. Add the sausages to the skillet and cook over moderate heat until golden and cooked through, 8 to 10 minutes; transfer to a platter.
Wipe out the skillet with a paper towel. Add the reserved 3 tablespoons of sage butter to the skillet. Add the scallions and cook over moderate heat, stirring, for 2 minutes. Add the potatoes, season with salt and pepper and stir until warmed through. Top the sausages with the potatoes, garnish with scallions and serve.