Begin by melting the butter in a Dutch oven or heavy pot over medium heat, then add the diced onion and sauté for about 5 minutes until it becomes soft and fragrant.

Next, whisk in the flour, stirring continuously until it attains a light golden color, then slowly add the milk while whisking for 2 to 3 minutes until the mixture thickens.

Incorporate the minced garlic and diced potatoes, mixing well, then increase the heat to high and allow the mixture to come to a gentle boil while scraping any browned bits from the pot.

Once boiling, reduce the heat to simmer for about 12 to 15 minutes, stirring occasionally until the potatoes are tender but firm, then take it off the heat, add in the ham, and stir well.

Season with salt and pepper to your taste, then gently mix in the sour cream and half of the shredded cheddar cheese.

Ladle the soup into bowls, topping each serving with the remaining cheese, crispy bacon bits, and sliced green onions for garnish. Serve warm!