Step 1

In a large bowl combine the leftover colcannon or plain mashed potatoes with the whisked egg. Stir to combine.

Step 2

Sprinkle the flour over the potatoes one tablespoon at a time and mix well to combine before adding another tablespoon.

Step 3

Stir in the cheddar cheese and mix well. Add salt and pepper to taste.

Step 4

Use a large cookie scoop to portion out a ball of mashed potato dough. Form each ball into a patty, about 3" in diameter. Transfer to a baking sheet or platter (one that will fit in your refrigerator or freezer). Continue in this fashion until you've used up all the potato mixture. Transfer the potato patties to the freezer for about 5-10 minutes or until they firm up a little, without freezing.

Step 5

Add the panko to a shallow bowl and gently shake it into a single layer.

Step 6

Coat each of the patties evenly in the panko breadcrumbs and return to the baking sheet. Freeze for an additional 5-10 minutes. (If they're too soft, especially initially, they'll break apart when frying.)

Step 7

Heat a large nonstick skillet over medium to medium high heat. Drizzle in enough olive oil to coat the bottom of the pan. When the oil is hot and starts to moire and slick across the surface, it's ready to fry.

Step 8

Working in batches, gently add the potato cakes to the skillet and fry for 3-4 minutes until the bottom of the patty is golden brown.

Step 9

Carefully flip the patty (they'll be soft) by placing the fingertips of one hand over the patty and lifting with a spatula. Quickly flip the colcannon cakes and brown on the opposite side, another 3-4 minutes.

Step 10

Transfer the patties to a dish lined with paper towels. Continue to fry in this manner until you've fried all the patties.

Step 11

Heat the oven to 325° and keep the patties warm while you make the separate batches.

Step 12

You can keep the potato patty dough in the refrigerator for up to 5 days and just fry a few patties as needed when you want them.

Step 13

Uncooked patties can be frozen. Wrap them in parchment paper so they don't touch, then wrap in foil or freezer paper. Patties will keep frozen up to one month. Thaw before frying.

Step 14

Leftovers are great for breakfast with eggs and sausages or bacon.