In a large bowl, mash the potatoes until there are no lumps.
2. Step
Add the cheddar cheese, cream cheese, bacon, scallions, salt, pepper, and onion powder.
3. Step
Mix until smooth.
4. Step
Transfer the mixture to a baking sheet lined with parchment paper. Smooth out the top.
5. Step
Lay a 1-inch (2.5 cm) square of cheddar cheese in the center of a slice of ham. Fold the edges of the ham over the cheese, making a tight parcel. Repeat with the remaining ham and cheese.
6. Step
Press a ham-and-cheese square into the potato mixture, making sure to leave 1 inch (2-cm) of space on all sides. Repeat with the rest of the squares.
7. Step
Push the potato mixture around to cover up and seal the tops of the ham squares, then smooth out again.
8. Step
Freeze for 30 minutes, then slice the mixture into squares so each square has a ham square in the middle.
9. Step
Place the flour, eggs, and panko into 3 separate medium bowls.
10. Step
Dip a square into the flour, shaking off any excess. Dredge in the egg, then in the panko. Repeat with the remaining squares.
11. Step
Heat the oil in a large pot until it reaches 350°F (180°C).
12. Step
Fry the potato squares two at a time until golden brown, about 4-5 minutes, then drain on paper towels.
13. Step
Garnish the potato dippers with shredded Parmesan cheese and chopped parsley. Serve warm.
