Mandu are Korean dumplings stuffed with a mixture of various meats and vegetables. There are many variations of mandu. Some classic versions are gogi mandu (which has meat as the main ingredient in the filling), yachae mandu (vegetable), and kimchi mandu. The cooking method also varies. Mandu can be steamed, deep-fried, pan-fried, boiled, or used to make soup. Mandu are usually made in large quantities and frozen for later use. Frozen mandu are easy to prepare as a delicious snack, appetizer, or meal, making it a home-cooked favorite for my two kids away at school.
*Note: Gochugaru are Korean red chile pepper flakes which can be found in the Asian section of the supermarket or specialty Korean grocery stores.
**Note: Mandu are so versatile that you can use any type of meat you like (or none at all). Although pork is classic, I typically use two types of meat and/or seafood for the complexity of flavor: pork and beef or pork and shrimp.
Combine all of the ingredients in a bowl and set aside.
In 2 separate bowls, generously sprinkle salt over the zucchini and cabbage and set aside for at least 15 minutes (this process will draw out water, soften the texture, and add flavor). Squeeze out as much water as possible from salted zucchini and cabbage by hand. Transfer the zucchini and cabbage to a large bowl and combine with the remaining ingredients (except for the wrappers and vegetable oil) in a large bowl. Season with salt, to taste, and mix well by hand.
Place 1 heaping teaspoon of the filling on a wrapper. Wet the edges of the wrapper with water and seal tightly (pushing the air out with your fingers) into a half-moon shape. Repeat this process with the remaining wrappers.
For tuigin mandu (deep-fried dumplings), heat a deep skillet with about 2-3 inches of vegetable oil over medium-high heat to 350 degrees. Fry the dumplings for 2-3 minutes on each side until golden brown. Serve hot with sauce.
For mul mandu (boiled dumplings), bring a pot of water to a boil over high heat. Add the mandu a few at a time, stirring gently so they don't stick to the bottom of the pot), and cook until all of them come up to the surface. Serve hot with sauce.