Preheat oven to 212F/100C, steam setting (100% humidity).
Put the couscous into a shallow stainless steel pan and add the water or stock. Place the pan into the preheated oven and cook for 15 minutes.
1 cup couscous, 1 cup water
At the end of cooking, remove the pan from the oven and add the butter or oil. Fluff well with a fork, mixing in the butter/oil to coat the grains.
1 Tablespoon butter
Use the couscous immediately as a side dish to a tagine, casserole or stew, or allow it to cool and use in a salad. Cold couscous will keep, covered in the fridge, for a few days.
Video
Notes
If you'd like to cook larger grained couscous varieties by this method you absolutely can. Use 1 part couscous to 1 1/2 parts liquid in this case, and allow around 20 minutes steaming time, or until the couscous is chewy all the way through.
Traditionally, Moroccan couscous has Smen, a fermented butter, added to give it an earthy, savory, cheesy flavor. It’s not common in Western countries so I’ve specified regular butter or olive oil instead. I was taught by a Moroccan cook that you can add a teaspoon or two of crumbled blue cheese with the regular butter if you want to approximate a similar taste to the Smen; it might sound strange but it really does make the couscous taste amazing.