Add the cabbage to a large bowl along with the carrot, scallions, radish or turnip, Asian pear, garlic and ginger. Toss to combine.
Add the rice flour and 1 cup water to a sauce pan. Heat to a simmer, then whisk for 3-4 minutes until smooth and the mixture forms a smooth, loose paste.
Remove from heat and stir in the gochugaru. The chili flakes will bloom as the mixture cools.
Stir in the fish sauce, salted shrimp, and miso paste (or your other umami alternatives).
Pour the mixture into the cabbage and vegetables. With your hands, rub the gochugaru mixture into the vegetables, covering them as completely as possible. Be thorough. Really get in there with your hands!
Taste and adjust for salt or any other desired seasonings.
Pack the kimchi into a large mason jar (or several). You can use other vessels, like a fermentation crock. Press the contents down and weigh it down with glass fermentation weights (or use a plastic bag filled with water).
Cover with a fermentation airlock lid, or use fermentation membranes (see notes). If you don’t have such lid options, use a 2-piece lid, but don’t screw it down, just set it on top. This is to allow any gases to escape while fermenting.
Set aside away from any sunlit areas and ferment for 1-3 days at room temperature (you CAN ferment longer if you’d like – see RECIPE NOTES on fermentation times). Moisture should release from the kimchi, so press the kimchi down if needed to keep it below the liquid. Gases should escape via the fermentation membrane, or just loosen the lid to let any gas build up out.
Set into the refrigerator and let sit for 1 week to let the flavors mingle. You can enjoy it right away, but it is better to wait. The fermenting kimchi will continue to ferment slowly in the fridge.
Use as desired.