Preheat oven to 425 degrees. Clean, then fork the potatoes a few times, carefully. Wrap them in a damp paper towel and microwave, on a microwave safe dish, for 5 minutes. This will allow for a quicker cook time in the oven.
Place potatoes on a baking tray and cook for 45 minutes, flipping halfway, or until fully cooked and soft.
Once finished, remove the skin from the potatoes.
Melt margarine in a small saucepan over medium heat. Add in the minced garlic and seasonings. Add in the potato and use a potato masher to completely mash up the potato.
Add in the milk and yogurt and toss to combine.