Make sure the pork leg is clean and place it in a large non-reactive roasting pan (make sure it will fit in the fridge as well as the oven). You can also use a large turkey marinating bag to marinate it in.
Rub or drizzle the lime juice all over the pork leg,
To prepare the “aliño” marinade you can mix the crushed garlic, ground cumin, salt and pepper directly in a bowl. If you want the extra rich red color, you can also add a tablespoon of achiote or annato powder to the mix. An easier option is to blend the whole garlic cloves with the onion/shallot, the spices, and a cup of beer.
For extra flavor in the meat itself, make several deep incisions on the meaty parts of pork leg and begin stuffing the incisions with the “aliño” or blended marinade mix. You can also score or cut into the skin, either simple vertical or horizontal lines or a cross hatch patter, if you want it to have that look, or if you prefer you can keep the skin completely intact - either option will work for this roasted pork hornado.
Pour the liquids (mix of beer, cider, and/or orange juice) over the pork leg.
Let the pork leg marinate and rest for 24-72 hours in the fridge. You can turn the leg around as need (or use the marinating bag to help concentrate the marinade all around the leg).
Pre-heat oven to 400F (200C).
In the meantime, in a small saucepan, melt a stick of butter on low heat, stir in the 1 tablespoon of the ground achiote and mix well. You can also add a bit of salt if desired (or if using unsalted butter).
If using a marinating bag, remove the pork from the bag and place it in - skin side up - a large roasting pan, with the marinating juices. Use paper towels to dry off the skin side up and any part of the skin that isn't in the liquid.
Drizzle and brush the melted achiote butter mix all over the dry pork skin. Keep any remaining butter mix to use to baste the pork skin during baking - and melt the additional stick of butter with achiote as needed.
Bake the pork leg - skin side up and uncovered - at 400 F (200C) for about 30 minutes.
Lower the oven temperature to 325F and bake for 3 hours. If the pan juices start to dry up, heat additional beer until warm with a bit of the achiote butter and add it to the pan. You can also brush and baste the pork skin directly with the achiote butter mix every hour or as needed. Rotate the baking pan as needed to keep the pork cooking evenly. If the skin starts to brown too much then cover it with foil -without pressing the foil directly on the pork skin.
If you have space in the roasting pan and want to cook the potatoes with the pork leg, add them at this time. If the potatoes are large or medium, it's best to cut them in half to make the sure they will be fully cooked. Another option is to use fingerling or baby potatoes, they take up less space and will cook better.
Continue baking the pork leg at 325F for another ~3.5 to 4 hours. The internal temperature of the pork leg should be 145F minimum - and it generally takes 15-20 minutes per pound of pork. If you covered the pork leg with foil remove it during the last 20-30 minutes to allow the skin to get crispy. You can also sprinkle some cold water on the skin and then put the oven on broil for the last 5 minutes (optional).
Serve with your choice of side dishes including the potatoes baked with the pork leg, mote or hominy corn, agrio sauce, curtido de cebolla y tomate, avocado slices, lettuce, and aji hot sauce. Other popular side dishes for hornado include rice, boiled yuca or cassava, habas or fava beans, and llapingacho potato patties - you can even make the llapiganchos using the potaoes that were baked with the pork leg.