In a big bowl, combine the cooked and cubed russet potatoes, diced bacon, diced green onions, sour cream, 1 teaspoon salt, and ½ teaspoon pepper. Use a potato masher or fork to mash everything together until mostly smooth. It's okay to have some small potato chunks for texture.

Cut the block of cheddar cheese into strips about ¼ inch thick.

Take a spoonful of the potato mixture and flatten it in your palm. Place a strip of cheddar cheese in the center and wrap the potato mixture around it, forming a ball. Make sure the cheese is fully covered by the potato mixture. Repeat until all the potato mixture is used.

Set up three bowls for coating: one with flour, one with beaten egg, and one with a mixture of cornstarch and panko breadcrumbs. Roll each potato stick in flour, then dip it in the beaten egg, and finally coat it in the panko breadcrumb mixture.

Pour the vegetable oil or canola oil into a deep fryer or a large pot, making sure it's at least 2 inches deep. Heat the oil to 350°F (180°C).

Carefully place the coated potato sticks into the hot oil using tongs. Fry them for about 3 minutes or until they turn golden brown and crispy on the outside.

Once the sticks are golden brown, remove them from the oil using a slotted spoon and transfer them to a plate lined with paper towels to drain any excess oil. Sprinkle them lightly with salt while they're still hot.

If you prefer baking, preheat your oven to 400°F (200°C).

Place the coated potato sticks on a baking sheet lined with parchment paper. Drizzle them with a bit of olive oil and sprinkle with salt. Bake for approximately 15 minutes or until the cheese is completely melted in the middle and the outside is a light golden brown.

Let the potato cheese sticks cool for a few minutes before serving, as they will be very hot straight out of the oven or fryer. Enjoy your crispy, cheesy potato sticks as a tasty snack or appetizer!