In a small saucepan over medium-high, heat the oil until shimmering, then pour the hot oil over the scallions; the scallions will sizzle. Stir, then stir in the fish sauce, ginger and sugar. Cool to room temperature. In a 12-inch skillet over medium-high, heat 1 tablespoon neutral oil until barely smoking.
Serve, smothering with plenty of scallion cream cheese sauce! Make sure you soften your cream cheese before trying to stir in the scallions, butter, and seasoning. If you forget to take your cream cheese out to soften, microwave it in a medium bowl at 50% power in 20-second intervals until softened.
You could serve the ginger scallion sauce over pretty much any protein, like chicken, shrimp, or pork. If you don’t have white pepper for the sauce, use black pepper. Swap the barramundi for any thick white fish, like halibut, cod, or mahi mahi.