Peel and cut potatoes into similar-sized chunks and place them in a large pot covered with one inch of cold water.
Boil until potatoes are fork-tender (approximately 15-20 minutes).
While the potatoes are cooking, prepare the bacon. Line a large microwave-safe plate with paper towels. Place 4-5 bacon strips on the paper towels, ensuring they are not touching. Cover with more paper towels and microwave on full power for 4 minutes. Continue to microwave in 30-second intervals if needed, until bacon is crispy. Remove the bacon from the plate and repeat the process until all of the bacon is cooked. Once cooled, crumble the bacon into small pieces.
When potatoes are done, drain them in a colander and return to pot. Add butter, milk, salt and white pepper and mix using an electric hand mixer.
Set aside a handful of cheese and a handful of bacon, and stir the remaining cheese and bacon into the mashed potatoes.
Spoon mashed potatoes into a 1.5-2-quart casserole dish and top with the reserved cheese and bacon.
Bake for 20-25 minutes or until top is golden brown.
Notes
Avoid Overmixing: Overmixing can break down the starches too much, causing the potatoes to have a gluey, gummy texture. To avoid this, mix just until the ingredients are combined and the potatoes are smooth. This will help you achieve that perfect, fluffy consistency.
Shred Your Own Cheese: For the best melt and flavor, shred your own cheddar cheese rather than using pre-shredded. Pre-shredded cheese often contains anti-caking agents that can prevent it from melting smoothly.
Broil for Extra Browning: If you want an extra-crispy topping, switch your oven to the broil setting for the last 2-3 minutes of baking. Be sure to keep a close eye on it to prevent burning.