In one sentence, describe what the following article is about:

Open one 14-ounce or 400 g can of pineapple chunks and drain the juice into a shallow dish. Set the pineapple chunks aside. Get out 1½ pounds (680 g) of chicken pieces and place them in the dish with the pineapple juice. Cover the dish with plastic wrap and refrigerate the chicken in the pineapple juice for at least 30 minutes or up to 2 hours. Pour 3 tablespoons (45 ml) of cooking oil into a large pot and turn the heat to medium. Peel 1 small onion and dice it into small 1/2-inch (12 mm) pieces. You'll also need to dice 1 medium plum or roma tomato. Mince enough garlic to get 1 teaspoon (2 g). Put the diced onion, tomato, and garlic into the hot oil and stir the vegetables as they cook. Sauté the mixture over medium heat until the onion softens a little and the garlic smells fragrant. This should take about 5 minutes. Stir ¼ teaspoon (0.5 g) of ground black pepper into the vegetable mixture and remove the marinated chicken from the refrigerator. Place the pieces of chicken in the pot in a single layer. Turn the heat up to medium-high and brown the chicken for 3 to 4 minutes. Use tongs to turn the chicken pieces over, so they brown on the other side. This should take another 3 to 4 minutes. Pour the pineapple juice from the marinating dish into the pot with the chicken pieces and vegetables. Heat the mixture over medium-high heat until the pineapple juice boils. Pour in 1 cup (240 ml) of coconut milk and turn the heat down to medium. The liquids in the pot should bubble gently. If you prefer to make a classic pininyahang manok, you could use milk or evaporated milk instead of coconut milk. Put the lid on the pot and let the chicken mixture bubble gently until the chicken pieces are completely cooked. This should take about 40 minutes or until they reach 160 °F (71 °C) with an instant read thermometer. Stir in 1½ tablespoons (22 ml) of fish sauce and the reserved pineapple chunks from the can. Keep simmering the mixture over medium heat for another five minutes. Peel 2 small carrots and use a knife to slice them into 1/2 inch (12 mm) thick diagonal slices. Stir the carrot slices into the pot and simmer the chicken mixture for another 5 minutes. Wash and trim the stems from 1 small red bell pepper and 1 small green bell pepper. Rinse out the seeds and use a knife to slice the peppers into 1-inch (2.5 cm) chunks. Stir the peppers into the pot and simmer the mixture for three more minutes, so the vegetables soften. Once the vegetables soften a little, serve the pininyahang manok while it's still hot. Consider serving the dish with steamed rice, boiled potatoes, or rustic bread. Store the leftover pininyahang manok in an airtight container in the refrigerator for three to four days.

Summary:
Drain the pineapple juice and combine it with the chicken pieces. Marinate the chicken in the juice for at least 30 minutes. Heat the oil and chop the onion, tomato, and garlic. Sauté the onion, tomato, and garlic for five minutes. Stir in ground pepper and add the marinated chicken pieces. Sear the chicken pieces for 6 to 8 minutes. Pour the pineapple juice into the pot and bring it to a boil. Stir in the coconut milk and reduce the heat. Cover and simmer the chicken for 40 minutes. Stir in the fish sauce and pineapple chunks. Add the carrots and simmer the mixture for 5 more minutes. Add the bell peppers and simmer them for three minutes. Serve the pininyahang manok.