Heat olive oil in large pot or skillet. Dice onions into chunks and add to skillet, sautéing until soft. Chop cauliflower into bite-size pieces and add to skillet along with curry powder. Cook for 1 minute.
Stir in 1 cup vegetable broth and ½ cup coconut milk. Bring to a boil, reduce to a simmer, and let cook until cauliflower is tender and sauce has thickened into a pizza-sauce consistency. Add more broth or coconut milk if needed to thin down to have a sauce. Taste occasionally and add curry powder or salt if needed. Let cool slightly.