You can cook this Colcannon on the stove. Here's how: Step 1. Put the potatoes in a medium pot and cover with cold water by 2 inches and add 2 tbsp of salt. Cook for 20 minutes or until tender. Drain well. Step 2. Melt butter, cook scallions and cabbage over medium-high heat for 2 minutes or until they are wilted. Step 3. Transfer all of the ingredients into a large bowl and use a hand masher to mash the potatoes. Season with salt and black pepper if necessary.