Prep: 1. Combine rice and water, bring to a boil. Cover and simmer for 20 minutes. (or use a rice cooker) Let sit for about 10 minutes, off heat and still covered before serving. 2. Meanwhile, mince garlic and scallions. Make: 1. Heat oil over medium-high heat, add garlic and scallions and cook for about 1 minute. 2. Add beef and cook, stirring occasionally, until browned, 3 to 4 minutes. 3. Add the five-spice powder (if using) and sugar and stir to combine. Add soy sauce, vinegar, 2 tablespoons water and bring to a boil. 4. Reduce heat to a gentle simmer and cover partially. Cook until beef is completely tender and sauce has thickened, about 15 minutes.
The five spice powder is totally optional (but delicious). If you can't find it, use a scant 1/4 teaspoon of as many of the following as you have: cinnamon, cloves, ground fennel, star anise, peppercorns (the last three are best toasted and then ground). We love to top this with an egg and extra scallions!