Cut cabbage head in half, making sure to split the core evenly. Cut each half into four wedges, taking care to leave some core on each so the wedges stay together. Place wedges in a single layer on a baking sheet and brush with canola oil on both sides.
Place cabbage in oven. Cook for 30 minutes, flipping halfway through.
While that is in the oven, make the dressing. Cook garlic in a little bit of olive oil. Whisk together remaining olive oil, lime juice, fish sauce,cilantro, salt, cayenne pepper, and sugar. When serving, pour dressing over cabbage.
Recipe by Things I Made Today at https://www.thingsimadetoday.com/2013/03/11/salmon-and-roasted-cabbage-with-spicy-lime-dressing/