1) Boil the whole potatoes in a pot filled with enough water to completely cover the potatoes. About 30 to 45 minutes.
2) Once the potatoes are cooked, take them out of the pot and set them aside on a plate to cool for about one hour.
3) While the potatoes are cooling, chop the green onions and tomato into small chunks and saute these in the butter (or olive oil) adding the garlic, cumin, 1 teaspoon of salt and pepper. We call this the “Hogao”.
4) Cook the hamburger meat in a frying pan with a couple of tablespoons of vegetable oil until it is no longer pink. Do not overcook. While the meat is cooking, add the corn starch, the remaining salt and more cumin if you wish. Make sure that the meat turns out crumbly with no large chunks.
5) Thoroughly mix the “hogao” and cooked hamburger meat in a bowl and set aside to cool.
6) Cut the potatoes in half. Now we come to the tricky part. In other countries, they mash the potatoes and simply make round balls out of them. We do it the hard way in Colombia. Take each potato half and scoop the middle of it out with a spoon so that you end up with a small “potato bowl”. Be careful not too scoop too much out as you may accidentally go through the skin and the potato may fall apart on you.
7) Now, take the scooped out potato “meat” and cut through it with a sharp knife. Don’t use a fork because it may turn into “mashed potatoes” and the texture will be much better the coarser it is.
8) Place the potato “meat” in the bowl with the hamburger and hogao and mix thoroughly, making sure that there are no really large chunks of potato in the mixture.
9) Add the cooked rice to the mixture and mix thoroughly once more.
10) With your fingers, take some of the meat/rice mixture and fill the middle of the potato bowls with enough mixture to form a dome. In other words, shape the mixture so that it now looks like you have a whole potato again.
11) Heat your oil to frying temperature.
12) Beat together the large eggs, milk and the flour until smooth. (I add a little salt, pepper and cumin to my batter but it is up to your taste).
13) Roll each stuffed potato in the batter until well covered and drop into the hot oil using a slotted spoon. Cook until golden on one side, roll over and cook the other side.
14) Remove potatoes from the oil and drain on a plate or platter lined with a thick layer of paper towels on the bottom.
15) Enjoy! I like to use squeezed lemon or a mild salsa on my papas rellenas but they are delicious just by themselves.
Hint: Sometimes, as you deep-fry the potatoes, you may notice that the batter may slide off leaving a blank spot on your potato. What I do, is that I use a teaspoon to pour some of the raw batter over the spot, carefully slosh some of the hot oil over it with the slotted spoon to set the batter and roll it over once more to cook the spot.