Recipe note: Refrigerate perishable leftovers promptly in shallow containers; use within 3–4 days and reheat to 165°F. Count storage from the original cooking date when using leftovers.
Have the sauce and thawed peas ready
Mix the brown sugar, soy sauce and measured sriracha before the skillet stage. Keep the optional extra sriracha separate for the table. Starting with a mixed sauce makes it easier to coat the noodles evenly instead of trying to dissolve sugar while turning a full pan.
The peas are measured thawed, and the noodles are cooked and drained separately. Have both ready, with the scallion and cilantro prepared, before starting the eggs. The final toss is brief and is not a replacement for the noodles' package cooking instructions.
Keep egg curds distinct during the final toss
Draw the spatula across the pan and fold the setting eggs into curds. Finish that stage with no liquid egg visible before adding the peas. Gentle turns help keep pieces of egg recognizable as the hot peas, noodles and sauce are brought together.
Lift noodles from the bottom when tossing so the sauce reaches more than the top layer. Finish with the scallion and cilantro, then divide the pan into its two portions. Offering the additional sriracha at the table lets each person decide whether to add it without changing the measured sauce for the whole batch.
Timing and servings are estimates. Equipment, ingredients and portion sizes affect the result.