Toast the 2 Tbsp of Cumin Seeds (the total you will need in this recipe) in a skillet over medium heat, stirring constantly, until they start to pop and smell fragrant. Immediately transfer to a stone-mortar or spice-grinder before they burn.
Grind them into a consistency that resembles coarsely ground black pepper, then set aside. Use this ground cumin for the marinade and seasoning in this recipe.
To make the marinade, combine Soy Sauce (1/2 tablespoon), Ground Cumin (1 teaspoon), Corn Starch (1 teaspoon), Dark Soy Sauce (1/2 teaspoon), Ground Coriander (1/2 teaspoon), Crushed Red Pepper Flakes (1/2 teaspoon), Toasted Sesame Oil (1/2 teaspoon), Garlic Powder (1/4 teaspoon), Ground White Pepper (1/4 teaspoon) and Sichuan Peppercorns (1/8 teaspoon).
Slice the Lamb (8 ounce) and scatter it on a chopping board in 1 single layer, then “tap” them all over with a sharp knife, aiming at scoring/tenderizing the meat without cutting through. Do this thoroughly. It allows the marinade to penetrate, and gives the lamb a more interesting texture.
Then mix the lamb with the “marinates”, using your hands to really distribute the seasonings evenly. Let marinate for at least 2 hours.
Get four separate bowls to make the seasonings. In the first bowl, combine the Red Onion (1/2) and Bean Sprouts (1 cup).
In the second bowl, Garlic (4 clove), Fresh Ginger (2 teaspoon), Asian Red Chili (1), Ground Cumin (1 1/2 tablespoon), Ground Coriander (1 teaspoon), Cayenne Pepper (1 teaspoon), Ground White Pepper (1/2 teaspoon), Ground Black Pepper (1/4 teaspoon), and Ground Sichuan Pepper (1/8 teaspoon).
In the third bowl, combine the Soy Sauce (2 tablespoon), Rice Wine (1 tablespoon), Rice Vinegar (1/2 teaspoon), Brown Sugar (1/4 teaspoon), MSG (1/4 teaspoon) and Salt (1/8 teaspoon).
In the fourth bowl, combine chopped fresh Fresh Cilantro (1/4 cup) and chopped Fresh Mint (1 tablespoon).
To make the hand-smashed noodles, add Chinese Dumpling Flour (1 1/2 cup), Salt (1/4 teaspoon), and Water (1/2 cup) in a stand-mixer bowl (or with a hand-held mixer if it comes with dough-hooks) (hand-kneading not recommended).
Start mixing on low then gradually increase the speed to high, and knead for 5 to 6 min. The dough will feel shaggy and a bit dry in the beginning, but as the flour absorbs water and glutens forms, it will become smooth and elastic.
It will be sticky but pulls away cleanly from the bowl during mixing. You should be able to “tap” the dough quickly with your finger without it sticking, and pull it slowly upward into 12″ (30 cm) long without breaking. If the dough breaks, either it’s not kneaded sufficiently or it’s too dry. Try kneading it for another 3 minutes first, before adding more water to get the correct consistency.
Place in a greased bowl and cover with plastic wrap, and let rest for at least 1 hour. Line a large baking sheet with parchment, set aside.
Prepare a small cup of canola oil within your reach. Oil your hands well, then transfer the dough onto an oiled surface. Roll out into an approximately 1/2″ (1 cm) thick, rectangular shape, then cut into 10 long strips.
Separate and lightly oil each strips so they don’t stick back to each other.
Take 1 strip and lay flat on the counter, then with oiled palm, start smashing/pounding the strip outward into a long, wide and flat noodle. Don’t worry about evenness or straight edges because it doesn’t matter.
Now pick up the noodle on both ends, lift it and gently tap it on the counter while stretching it out slightly. You don’t have to try hard. The noodle WANTS to stretch out and gravity will pretty much do the job for you! Carefully not to make the noodles too thin or they will lose their desired texture (you shouldn’t be able to see through it).
Lay the noodle flat, without any foldings, on the parchment-lined baking-sheet. Repeat with the rest (lay a new parchment over the top once you run out of space).
Bring a large pot of water to boil. Meanwhile, heat another large deep skillet/wok over high heat. Mix 2 Tbsp Canola Oil into the marinated lamb to lubricate/separate the pieces, then add to the hot skillet as spread out as possible.
Let caramelize for 30 sec without moving, then start sautéing just until they are no longer pink. Add the first bowl with the onions and bean sprouts and cook just until it starts to soften, then transfer to a bowl.
Add Canola Oil (4 tablespoon) to the same skillet until hot, then add the seasonings from the second bowl. Cook until fragrant without burning the garlic, then add the third bowl. Turn off the heat while you cook the noodles.
Add the noodles, one by one, into the boiling water. Cook just until they float to the surface (it will take less than a min), then drain/transfer to the skillet.
Turn the skillet heat back on high, then add the lambs/onion and gently toss everything together. Finish with the final bowl of chopped herbs.
Serve immediately with Chili Oil (to taste), and I like to sprinkle a bit more ground cumin on top.