1. In a 5- to 6-quart pan over high heat, bring about 3 quarts water and 1 teaspoon salt to a boil. Add orzo and cook until barely tender to bite, 5 to 9 minutes. Drain well. Pour into a bowl and mix with olive oil. Rinse and dry pan.
2. In the same pan, over medium heat, melt butter. Add shallots and stir often until they start to brown, 3 to 4 minutes. Add the garlic and orzo; mix well and cook just until pasta is warm, 2 to 5 minutes. Remove from heat and stir in green onions and salt and pepper to taste. Mound in a serving bowl and serve warm.