Step 1

Toss steak in a medium bowl with sugar, sesame oil, 1 tsp. soy sauce, and 1 tsp. salt to coat and let sit 20 minutes.

Step 2

Place a large skillet over high heat. Pour in vegetable oil and swirl to coat bottom of pan. The oil should be shimmering and you should see some wisps of smoke—if it’s not hot enough, the meat will steam instead of getting deeply browned.

Step 3

Add steak to skillet in an even layer (it’s okay to crowd it a bit) and cook, undisturbed, until brown around the edges, about 2 minutes. Turn steak over and add onion, ginger, lots of pepper, and ⅓ cup water. Cook, tossing often, until onion is just tender and ginger is softened, about 2 minutes.

Step 4

Remove skillet from heat and add butter, lemon juice, and remaining 1 Tbsp. soy sauce. Toss until butter is melted and coats steak. Taste and season with more salt if needed.

Step 5

Divide rice among bowls and top with beef stir-fry.