1. Peel the potatoes. Cut each potato into 8 large chunks. Place the potatoe chunks in a large pot. Pour the box of broth over the potatoes and add 1 cup of water (more or less) so that the potatoes are just covered by the liquid. Turn heat up to high and bring to a boil. Cook until the potatoes are very tender when you stab them with a fork (like so tender they just break apart), this should take about 20-25 minutes.
2. Drain the water and allow the potatoes to sit in the collander until the potatoes stop steaming completely. This may take about 10 minutes but it prevents your mashed potatoes from tasting watery!
3. While you are waiting on your potatoes to release the steam, heat a small saucepan over medium heat. Melt your butter in the pot. Now add the milk and the garlic and bring it to light boil. Turn heat down to medium-low or low and allow to simmer lightly until you are ready to mash your potatoes.
4. Once your potatoes are done steaming, place them back into the empty large pot. Pour the milk/butter mixture over the potatoes in three different parts while mashing. Pour and mash, pour some more then mash, and finally, pour and mash again. Mash until the potatoes are the consistency that you want them. If you really like them creamy without ANY clumps, use a hand blender on low until they reach the consistency that you want. (Side note: If you leave your potatoes on the stove for a long period of time just to keep warm, you may need to add 1/4-1/2 cup of chicken broth before serving just to add some more moisture. They tend to dry up sometimes).