Cook pork roast approximately 20 minutes per pound at 325 degrees Fahrenheit. All pork roasts should be cooked to an internal temperature of 145 degrees F. After roasting, let the roast stand for a minimum of three minutes.
A classic recipe for pork roast involves a 4- to 5-pound roast, garlic and a small onion. Two cups of water, pepper and salt to taste, a tablespoon of lard and 2 tablespoons of cornstarch round out the recipe. To begin, place the lard in a Dutch oven or a pot with a heavy bottom and lid, and melt it over medium high heat. Season all sides of the roast with a savory rub, and place it into the pot when the lard starts to smell hot. After the roast has cooked in the lard for a minute or so, turn it so all sides brown evenly.
Slice the onion and arrange (along with five garlic cloves) around the roast. Pour in 2 cups of water and bring all to a boil. Put the lid on the pot, place in the oven and roast for the set time, depending on weight. Add cornstarch at the end of the roasting process but before bringing the water back to a boil. After tasting and seasoning as needed, the roast is done.