Cook the quinoa according to the instruction on the package. Once cooked, season with salt and pepper to taste. Cover with a lid to keep warm.
Heat a nonstick pan on medium heat. Once hot, add the oil. Saute the onion, carrot, celery, squash, and zucchini until the celery starts to soften. Stir in the garlic and ginger; saute until the vegetables begin to soften.
Crumble in the turkey and brown while breaking it up into smaller pieces until it is no longer pink. Season with salt and pepper.
Stir in the lemongrass, tomato, vinegar, broth, and soy sauce. Bring to a simmer, stirring occasionally, so the flavor builds.
Slowly stir the cornstarch mixture a little at a time into the pan to thicken to a creamy consistency. (Add more or less cornstarch slurry as needed) Remove from the heat. Season with salt and pepper if needed.
Serve with quinoa. Garnish with scallion.
Notes
Pro tip: Use any extra vegetables you would like or have on hand that aren't going to be used.