When I knit a shawl in two-color brioche, starting from the neck, I first make a tab in two-color brioche rib. Then I pick up stitches from the edges of the tab. Here is how I picked up the stitches for Humus shawl. I don’t know if there’s an official name for the method. I’m calling it brioche rib tab, since the tab is knitted in brioche rib, and the cast-on method resembles the garter tab cast-on.