Just a note, beets, potatoes, onions take the longest (25 minutes) while leafy greens take only about 5-8 minutes, however, you can decide on the textures you prefer. Keep in mind that slicing the vegetables in even pieces (either larger or smaller) makes a difference in cooking time too. Once you've tried this a couple of times and become comfortable with it, the whole process should only take about 30 minutes to complete.
I also thought that I would include a list of winter, seasonal vegetables for consideration the next time you are at the grocery store.
Artichokes, Avocado, Bok Choy, Broccoli, Broccoli Rabe, Brussel Sprouts, Cabbage, Cauliflower, Chestnuts, Jerusalem Artichokes, Kale, Lettuce, Parsnips, Radishes, Rhubarb, Rutabaga, Snow Peas, Squash (winter), Sweet Potatoes, Turnip (white), Watercress
Because of the specific nutritional make-up of winter vegetables, eating them regularly (every day) will help to ensure a healthier immune system and balanced energy levels.