Step 1

Melt butter in a skillet over medium heat.

Step 2

Cook and stir onion and garlic in the melted butter until onion is tender, 5 to 7 minutes.

Step 3

Preheat a waffle iron according to manufacturer's instructions.

Step 4

Combine onion mixture, mashed potatoes, flour, eggs, salt, and black pepper in a large bowl until well blended.

Step 5

Scoop 1/4 to 1/2 cup batter (depending on size of waffle iron) into the center of waffle iron and close lid. Cook until golden brown, 3 to 5 minutes.