Again, this recipe has been around so long I’m not sure where it came from.
1 (13.5- to 14-oz.) can coconut milk, divided 1/4 cup red curry paste 1 cup lower-salt chicken broth, or homemade chicken or vegetable broth 2 tablespoons light brown sugar or light brown palm sugar; more as needed 1 teaspoon fish sauce; more as needed 1 cup sliced butternut squash (1/4-inch-thick bite-size slices) 1 cup bite-size green bean pieces, optional 3 1/8-inch-thick slices fresh ginger or galangal 3 stalks fresh lemongrass, trimmed, bruised, and cut into 3- to 4-inch pieces 1 pound beef strip steak, cut into 1/4-inch-thick bite-size slices 1/4 cup loosely packed chopped fresh cilantro (leaves and tender stems) Fresh red chiles, cut into 1/8-inch strips or sliced into rings, for garnish
Shake the can of coconut milk or stir it well (this creates a consistent thickness, since the fat often solidifies at the top of the can).
In a 3- to 4-quart saucepan or wok over medium heat, simmer 1/2 cup of the coconut milk, stirring occasionally, until reduced by about half, 3 to 5 minutes. It will get very thick and shiny and may or may not separate; either is fine.
Add the curry paste, whisk well, and cook, continuing to whisk, for 1 minute. Whisk in the broth, sugar, fish sauce, and remaining coconut milk. Bring to a simmer over medium-high heat.
Add the butternut squash, green beans (if using), ginger slices, and lemongrass pieces and continue to simmer, adjusting the heat as necessary. After 2 minutes, add the beef and continue to simmer until everything is tender and cooked through, about 3 minutes more.
Remove the curry from the heat. Season to taste with more sugar and fish sauce, and stir in the cilantro. Transfer to a serving bowl (or serve right out of the pot). Remove the ginger and lemongrass or tell your guests to eat around them. Garnish with the red chiles.