Mix cream cheese, crab, garlic powder, sugar, Worcestershire, salt, and spring onions until well combined. Pulse briefly in a food processor for a semi-chunky texture, if desired.
Preheat oven to 350°F (175°C). Brush a 9x13-inch baking dish with melted butter. Keep phyllo covered with a damp towel while working.
Layer one sleeve of phyllo in the pan, lightly buttering every 2–3 sheets. Spread filling evenly over the phyllo. Top with the second sleeve, again buttering every few sheets. Finish with remaining butter, fully coating the top.
Using a sharp knife, cut into diamonds or squares before baking. Bake for 40–45 minutes, until golden brown and crisp.
Cool for 10–15 minutes before serving. Serve warm with sweet Thai chili sauce on the side or drizzled over top.
