To make the sauce, prepare the rice “glue” by adding the sweet white rice flour with 1 1/2 cup of water in a small pot over medium heat. Use a whisk to stir the mixture continuously until it turns into a thick glue-like consistency (about 3 minutes). Set the “glue” aside and allow it to cool.
Meanwhile, place the apple (or pear), onion, scallion whites, garlic, ginger and plum syrup into a blender and blend on high until smooth (about 1 minute). Mix together the rice glue, the blended garlic mixture, scallion greens, carrot, radish, Fishy Sauce and gochugaru.
Pour the sauce over the rinsed cabbage leaves. Using your hands (wear gloves!), spread the mixture over the cabbage leaves to makes sure they are evenly and well coated. Place the kimchi into airtight containers (I use two 32-ounce mason jars), pressing down with each scoopful to remove air pockets. If you have a lot of space left at the top, sprinkle with a handful of salt (this will prevent the growth of any yeast).
Store the kimchi at room temperature for the first 24 hours. Then place in the refrigerator. Your kimchi will be ready to enjoy by the third or fourth day, though it will mature and taste even better if you wait a couple weeks.