Here's how I make potato croquettes.
1. First, sautee the meat - I use lean ground pork - in garlic and onion. I also add mushroom and hotdogs, but it's really optional.
2. Boil the potatoes. Once soft, mash them. Add a pinch of salt and pepper.
3. Using your hand, get a handful of the mashed potato and flatten it. Put the meat inside and shape the potato into a ball (you can actually make different shapes, like egg-shaped or cylindrical-shaped). I also add cheese in the filling. Ensure that the filling is thoroughly covered. Make sure also that the meat is dry - leave behind the oily sauce. (Also, don't make the potato ball too big - I made the mistake of making humongous balls, and they turn into disaster when I fried them - each bursts open because of the weight, spilling the insides! )
4. Roll the ball into beaten eggs and breadcrumbs.
5. Deep fry until golden brown.
Presto! Delicious home-made croquettes! It's a bit crunchy on the outside but soft inside. The meat and cheese taste yummy with the hot mashed potato. No sauce requried. It's best eaten with wine and cheese.