Bring 3 cups of water to a boil, add pasta, and boil for 8 minutes.
In the meantime prepare the broccoli and cauliflower florets, and chop/slice onions and black olives. Place these in a serving/storing dish.
When the pasta is done, pour it into a strainer over the sink to remove water.
Rinse the pasta for a second or two. Pour hot pasta over broccoli/cauliflower florets and chopped onions. Stir the ingredients together and cover to allow the heat from the pasta to steam the broccoli, cauliflower, and onions. Let that sit for about 10 minutes or so until the pasta has cooled.
Add the black olives and Italian dressing, stir until everything is well coated. Refrigerate for 30 minutes to an hour before serving.
Notes
*Use gluten-free pasta & dressing to make this a gluten-free pasta dish.I recommend using fresh broccoli and cauliflower, but you can use frozen.Rotini pasta is perfect for pasta salad because it traps the dressing in the folds.Use a low-carb pasta and a no-sugar-added Italian vinaigrette to make this into a low-carb side dish.