Preheat the oven to 425°F and line a large baking sheet with parchment paper.
Place the sweet potatoes on the baking sheet and toss with 2 teaspoons olive oil, garlic powder, salt, and black pepper.
Roast for 25 to 30 minutes, stirring halfway through, until tender and lightly browned.
Whisk the soy sauce, honey, rice vinegar, sesame oil, cornstarch, ¼ cup water, and crushed red pepper flakes in a small bowl until smooth.
Heat 1 teaspoon olive oil in a large skillet over medium-high heat.
Add the beef and cook for 3 to 5 minutes, stirring occasionally, until browned, then transfer to a plate.
Add the broccoli and 2 tablespoons water to the skillet, cover, and cook for 3 minutes.
Remove the cover, add the garlic and ginger, and cook for 30 seconds, stirring constantly.
Return the beef to the skillet.
Pour the sauce over the beef and broccoli and stir to coat.
Cook for 2 to 3 minutes, stirring frequently, until the sauce thickens.
Divide the roasted sweet potatoes among 4 bowls. Top with the beef and broccoli mixture.
Garnish with green onions and sesame seeds, if using.
Notes
Tips and Tricks
Slice the beef thinly - Thin slices cook quickly and are less likely to turn tough.Give the sweet potatoes room - Spread them out on the baking sheet instead of crowding them so the edges can brown.Keep an eye on the sauce - Once the cornstarch starts thickening the sauce, it can move quickly. Remove the skillet from the heat when the sauce coats the beef and broccoli.Adjust the heat - Leave out the crushed red pepper flakes for a mild bowl or increase them slightly for more spice.
Storing and Reheating
Refrigerator - Store leftovers in an airtight container in the refrigerator for up to 4 days.Microwave - Reheat individual servings until hot, stirring or turning the ingredients partway through heating.Skillet - Reheat the beef and broccoli over medium-low heat with a small splash of water if the sauce has become too thick.