1. Preheat your oven to 325°F.
2. Wash, peel (if desired), and dice the Russet or Yukon Gold potatoes into small cubes.
3. Dice the onions and mince the garlic.
4. Cook the bacon in a skillet until crispy, then crumble it into small pieces.
5. In a large mixing bowl, combine the diced potatoes, onions, garlic, shredded cheddar cheese, and crumbled bacon.
6. Add mayonnaise to the mixture and stir until all ingredients are evenly coated.
7. Lightly grease a 9×13-inch baking dish.
8. Transfer the potato mixture into the prepared baking dish, spreading it evenly.
9. Cover the dish with aluminum foil and place it in the preheated oven.
10. Bake for about 1 hour, then remove the foil and continue baking for another 30 minutes, or until the top is golden brown and the potatoes are tender.
11. Remove from the oven and let it cool for a few minutes before serving.
12. Garnish with optional toppings like green onions or olives for extra flavor if desired.
13. Serve warm as a hearty side dish or modify with additional meat for a main course.
14. Store leftovers in an airtight container in the refrigerator for 3-4 days or freeze for up to a month.
15. Reheat in the microwave or oven before serving again.