Over medium heat (5 out of 10) heat up large 5L pot, add enough vegetable oil just to cover the bottom.
Line the pot bottom with cut onion slices in one layer. Let it cook for 2-3 minutes.
Add 2 tbsp of smoked paprika and stir.
Add 2 bay leaves, 1 tsp black peppercorns, 1 tsp whole cloves, head of unpeeled garlic and horizontally cut in half. Stir it all together.
Sprinkle in 35g of salt to help softening the onions, stir it around and cook for another 2-3 minutes.
Put pork knuckle(s) in the pot and pour in the whole bottle (500 ml) of beer. Top it up with water just to cover pork knuckles.
Add 2 tbsp of sugar and bring it all to simmer. Put the lid on and over low heat (1-2 out of 10) have the liquid barely simmering for 2-4 hours.
Remove pork knuckle(s) and set on a plate. Try to set it up vertically so the skin is fully exposed. Let it cool to room temperature and then refrigerate, uncovered, for at least 8-12 hours.
Strain the broth and save about 300 ml. Put it in airtight container and refrigerate.
Sauce
Prepare all the ingredients including precutting onions, bell pepper and garlic.
Over high heat (10 out 10) add vegetable oil into preheated medium size sauce pan.
Sauté onions and peppers for about 5 minutes, stirring frequently.
Add chopped garlic, tomato puree, whole cloves, beer. Stir it all together and reduce heat to medium low (4 out of 10). Let it simmer for 5 more minutes.
Add sugar, lemon juice and Adjika. Stir all around and let simmer for another 2-3 minutes.
Using a stick blender, process everything together.
Cover the sauce pan and over low heat (1-2 out of 10), slow simmer for 15 minutes.
Pass the sauce through the sieve and let it cool to room temperature.
Day 2: Rulka Roasting
Pour the saved broth into a ceramic or glass dish with a low side. Place pork knuckle in the dish, ideally in vertical orientation exposing the skin all the way around.
Preheat the oven at 170ºC (340ºF), convection oven, circulation fan on.
Roast Rulka for 3 1/2 to 4 hours. Monitor the liquid level in the baking dish and add water as needed.
After 3 hours, baste the Rulka at least once with the juices and let it roast for another 30 min.
Inspect the doneness by knocking on the rulka’s skin with your finger nail. If it makes a hollow sound it is done, if not let it roast a little longer until that is accomplished.
Let the Rulka rest for at least 20 minutes before serving. Serve hot with dipping sauce.
Recipe Notes
make sure that pork knuckles are cooked at barely simmering liquid. You should see only an odd bubble that comes to the surface of the cooking broth. If you let it come to a full boil that will cause fat to render and meat to fall of the bones. The purpose of this stage is to infuse flavours to the meat.
pork knuckles are refrigerated uncovered in order to dry out and firm up the skin. This is important step in order to get a crisp crackling skin after roasting.