The surprisingly simple process of making homemade couscous yields a nuttier, more flavorful result than any boxed couscous.
Place 5 liters tap water in the base of a couscoussier (couscous steamer pot), and bring to a boil over high.
While water comes to a boil, stir together 1 cup warm water and salt in a bowl until salt dissolves. Pour into the glass spray bottle provided with couscoussier. Place semolina in the flat-bottomed bowl provided with couscoussier, and spray with about 12 spritzes salt water. Using a circular motion, rub semolina with your fingers until small (1/16- to 1/8-inch) clumps form, spritzing with up to 1/2 cup salt water, as needed.
Place rolled semolina into the sieve provided with the couscoussier. Using a clawing motion with your fingers, move rolled semolina aound until it passes through sieve into a large bowl. Sprinkle semolina with 4 teaspoons oil, and toss gently to coat. Lightly grease (with oil) bottom and sides of the perforated couscoussier steamer insert. Place rolled semolina in an even layer in steamer insert. Place insert over boiling water, reduce heat to medium, and wait until the first wisp of steam passes through the semolina. Cover and cook 20 minutes.
Wipe flat-bottomed bowl clean, and add partially cooked couscous. Using a wooden spoon, gently stir, breaking up any large clumps. Spray with about 12 spritzes salt water, and toss gently to incorporate. Sprinkle with 1 teaspoon oil, and toss gently to coat. Return couscous to steamer insert over medium heat, and wait until the first wisp of steam passes through semolina. Cover and cook 20 minutes.
Repeat step 4 with another 12 spritzes salt water and remaining 1 teaspoon oil, cooking until desired texture is reached, about 20 minutes. Pass couscous through sieve a second time, and transfer to a serving bowl.