2tablespoonssalt or to taste (start with 1 and gradually add after tasting
1cupdashimadried kelp broth (Boil 1 large piece of dashima in 2 cups of water for 10 minutes. You can add one or two dried shiitake if available.)
a large bowl or pot7 - 8 quarts
a large colander
a 3/4 - 1 gallon airtight container or jar
Cut the stem end of cabbage lengthwise in half only about 3 - 4 inches in. Then, slowly pull apart to separate into two pieces by hand. Do the same for each half to make quarters. Running the knife through all the way would unnecessarily cut off the cabbage leaves.
In a large bowl, dissolve 1/2 cup of coarse sea salt in 5 cups of water. Thoroughly bathe each cabbage quarter in the saltwater one at a time.
Using the other half cup of salt and starting from the outermost leaf, generously sprinkle salt over the thick white part of each leaf. Repeat with the rest of the cabbage quarters. Try to salt all the cabbage quarters with the 1/2 cup salt, but you can use a little more if needed. Set aside for about 6 - 8 hours, rotating the bottom ones to the top half way through.
Meanwhile, make the glutinous rice paste and the broth and cool. Prepare the other seasoning ingredients. Mix all the seasoning ingredients. Set aside while preparing the other ingredients until the red pepper flakes become pasty.
The cabbages should be ready to be washed when the white parts are bendable with a bit of resistance. Rinse thoroughly 3 times, especially between the white parts.
Drain well, cut side down.
Cut the radish into matchsticks (you can use a mandoline if available). Roughly chop the scallions and the optional mustard green. Transfer to a large bowl.
Combine with the seasoning mix. Mix well by hand. Taste a little bit. It should be a little too salty to eat as is. Let it sit for 30 minutes to an hour to allow the flavors to meld nicely.
Cut off the tough stem part from each cabbage quarter, leaving enough to hold the leaves together. Place one cabbage quarter in the bowl with the radish mix. Spread the radish mix over each leaf, one to two tablespoons for large leaves. Eyeball the stuffing into 4 parts and use one part for each cabbage quarter.
Fold the leaf part of the cabbage over toward the stem and nicely wrap with the outermost leaf before placing it, cut side up, in a jar or airtight container. Repeat with the remaining cabbages. Once all the cabbages are in the jar or airtight container, press down hard to remove air pockets. Rinse the bowl that contained the radish mix with 1/4 cup of broth (if any remaining) or water and pour over the kimchi.
Leave it out at room temperature for a full day or two, depending on how fast you want your kimchi to ripe. Then, store in the fridge. Although you can start eating it any time, kimchi needs about two weeks in the fridge to fully develop the flavors. It maintains great flavor and texture for several weeks.
You can also use a soft, well ripened, persimmon instead of pumpkin. These are two ingredients very common in Korean temple kimchi.