Recipe Belle's Cheesy Potato Stoup

Ingredients
6 potatoes, diced
1 (10.75 ounce) can condensed cream of onion soup
1 (12 ounce) can fully cooked luncheon meat (such as SPAM®), cubed
2 cups milk
1 (8 ounce) package shredded Cheddar cheese
1 pinch red pepper flakes, or to taste
salt and pepper to taste

Directions
Place the potatoes into a large saucepan and cover with salted water. Bring to a boil over high heat, then reduce heat to medium-low, cover, and simmer until the potatoes are tender, 10 to 15 minutes. Drain off all but 2 cups of the water, then stir in the cream of onion soup, luncheon meat, milk, and Cheddar cheese. Return to a simmer over medium heat, and cook a few minutes until hot. Season to taste with red pepper flakes, salt, and pepper.