Liang Fen (Cold Mung Bean Noodles with Chili Vinegar Sauce)

From 6 Bittersweets Guest Post
Adapted from Gourmet, my memory, etc.
Serves 4 to 6 as a snack/appetizer

XIAOLU’S NOTES: Please note the uncut jelly needs to chill for several hours and plan accordingly. You can make the jelly up to 1 day ahead. The Szechuan pepper oil will keep, covered and chilled, for 3 months. Bring to room temperature before using.

Jelly
3 cups water
7 Tbsp mung bean starch powder
1/2 tsp salt

Sauce
1 1/2 Tbsp soy sauce
1 Tbsp Chinese black vinegar (preferably Chinkiang)
2 tsp sugar
2 tsp Szechuan pepper oil, or to taste (Recipe below)
2 tsp red chili oil, or to taste
2 tsp roasted sesame oil
1 1/2 tsp finely grated or minced peeled fresh ginger
1 tsp finely grated or minced garlic
1/2 tsp Szechuan chili bean paste (Pixian doubanjiang 郫县豆瓣酱) OR finely chopped fermented black beans (rinse well first)
1/2 tsp roasted sesame paste (can substitute tahini) (optional)
3 large scallions (white and pale green parts only), cut into very thin shreds
Chopped green scallions, to garnish
Salt, to taste if needed

To prepare the jelly, oil an 8-inch square baking pan.  Mix together the water, mung bean starch, and salt until completely smooth, then bring it to a boil in a 2 to 3-quart heavy saucepan.  Continue to boil over moderate heat, stirring constantly, until the mixture is very thick and translucent, about 3 minutes. Transfer to the oiled baking pan and cool to room temperature, about 45 minutes. Cover surface with a lid or plastic wrap and chill until jelly is firm, about 2 hours.

To prepare the sauce, stir together soy sauce, vinegar, sugar, oils, ginger, garlic, chili bean paste OR black beans, and sesame paste in a large bowl until sugar is dissolved.

To assemble the dish, run a thin knife around the side of the pan to loosen the jelly, then unmold onto a cutting board. Cut jelly into 3 strips, then cut each strip crosswise into 1/4" slices. Carefully transfer to sauce in serving bowl or dish, then gently stir in scallions. Sample some and add salt to taste if needed. Garnish with more scallions, if desired, and serve with more Szechuan pepper oil and red chili oil on the side. Serve IMMEDIATELY. The noodles are best when the sauce coats but does not soak into the noodles so leftovers are not recommended.

Szechuan Pepper Oil
2 tsp Szechuan peppercorns
1/4 cup peanut or vegetable oil

Grind peppercorns coarsely in an electric grinder or with a mortar and pestle. Heat oil with peppercorns in a 1 to 1 1/2-quart heavy saucepan over moderate heat, swirling pan occasionally, until peppercorns turn a shade darker, about 1 minute, then transfer to a heatproof bowl and cool to room temperature. Stir before using.