SAUCE: Use a fork to whisk together the cornstarch and soy sauce in a bowl. Once smooth, add in the remaining sauce ingredients. Whisk until smooth and set aside.
VEGGIE & CHICKEN PREP: Prepare the veggies before you begin cooking, because once you start, it all goes quickly! Dice the onion. Finely mince the ginger and the garlic. Finely chop the broccoli (1/2 inch pieces). Thinly slice the green onions. Trim chicken thighs of excess fat and cut into very small (1/2-inch) bite-sized pieces. Once everything is cut, set a large pot of water to boil.
COOK CHICKEN: Heat 2 tablespoons oil in a large 12-inch skillet (or wok), over medium-high heat. When hot, add the onion. Cook, stirring frequently with a wooden spoon until the onion is turning golden, about 5-7 minutes. Add the garlic and ginger and cook for another 1-2 minutes or until fragrant. Press to the edges of the pan and add the chicken to the center of the pan in a single layer. Cook chicken until browned, but not cooked through, about 4-5 minutes. Incorporate the onion, garlic, and ginger as you cook the chicken.
RAMEN & BROCCOLI: Meanwhile, add the broccoli and ramen to the boiling water. Immediately press all of the ingredients under the water. Don't salt the water here; the sauce will season these ingredients. Cook, stirring occasionally for 90 seconds (See Note 2). Promptly remove and drain. Give everything a quick rinse (10 seconds) in cool water and then shake off excess water.
ADD SAUCE: Give the sauce one more quick stir and pour the sauce into the chicken and cook, stirring near-constantly until the chicken is fully cooked through, the sauce thickens and begins to bubble at the edges, about 2-4 minutes. Reduce the heat to low. Add the drained ramen and broccoli on top and gently toss with tongs to combine and coat the noodles.
GARNISH: Once everything is coated in the sauce, remove the pan from the heat. Add desired garnishes: a sprinkle of roasted and salted cashews, green onions, and sesame seeds. We usually add a drizzle of sesame oil and (for those that like heat) Sriracha to individual serving bowls. Enjoy hot.