Turn the handle to the unlock position, open the lid and turn the handle back to the lock position. Pour in salted water and let it boil by pressing the [MULTICOOK] function and press [COOK] with the lid open.
After the water boils, place the diced potatoes and garlic inside the pot and press the [MULTICOOK] function, set the cooking time to 20 minutes then press [COOK] until the potatoes are tender.
After 20 minutes of cooking, drain the pot and place the potatoes and garlic in a bowl. Add in sour cream, vegetable broth and butter into the bowl. Using a fork or masher or electric beater, mash the potatoes until smooth or until your desired texture.
Season with salt and pepper to taste and serve warm and top with fresh herbs, if desired.