Sometimes you’ll see a recipe calling for segments of an orange or a grapefruit. What they mean is the segments of those fruit without the pith — the pale, opaque membrane that surrounds each section of the fruit. Though there’s nothing particularly wrong with pith, it has the tendency to be bitter and chewy and aesthetically it takes away from the jeweled luster of oranges, grapefruits, mandarins and other citrus.
Peeling each individual segment by hand is a fools errand, but with a tiny bit of patience you can cut your way around it and be left with perfect segments to top any dish.
Once you’ve done that, hold it in your hand and, using a smaller knife, cut into the fruit right along the lines of the membrane on both sides. You should then be able to lift each segment out easily.