Preheat oven to 230 degrees C (450 F).
Line a baking sheet with aluminum foil for easy cleanup, if needed.
Dry the green beans thoroughly with a paper towel. Spread onto the baking sheet. Pour on olive oil and sprinkle with salt. Toss to mix well. Shake the pan and use a pair of tongs to arrange the green beans into a single layer, to ensure even roasting.
Bake for 12 minutes, until browned and almost tender.
While baking the green beans, prepare the garlic sauce. Mix soy sauce, chicken stock, sugar, and cornstarch in a small bowl.
Heat the olive oil in a small saucepan over medium heat until warm. Add garlic. Stir for a minute or until fragrant. Add the soy sauce mixture. Let cook until boiling. Stir and cook until the sauce thickens.
Pour the sauce over the green beans. Toss to mix well. Place them back into the oven and let bake for another 2 to 4 minutes, until the sauce is caramelized.
Serve warm as a side dish.
You can cook these green beans ahead and store them in an airtight container in the fridge for a day. Reheat at 180 C (350 F) in the oven or microwave until warmed through.