Whisk together 2 tablespoons of soy sauce and sherry in a medium bowl to create the marinade.

Slice the turkey across the short side into thin slivers, about 1/4 inch wide and 2 inches long.

Add the sliced turkey to the soy sauce marinade and stir to coat.

Season the turkey with pepper.

Let the turkey marinate while preparing other ingredients.

In a small bowl, whisk together lemon juice, 1/4 cup of water, sugar, and the remaining 1 tablespoon of soy sauce.

Whisk in the cornstarch until fully dissolved.

Set the lemon juice mixture aside.

In a separate small bowl, combine the minced green onions, jalapeno (if using), garlic, and gingerroot.

Heat a skillet, wok, or Dutch oven over high heat for 1 minute.

Add 1 1/2 teaspoons of oil, swirling to coat the bottom of the pan.

Stir in half of the marinated turkey.

Cook for 2 minutes, stirring constantly, until the turkey starts to become opaque.

Transfer the cooked turkey to a serving bowl.

Repeat with the remaining 1 1/2 teaspoons of oil and turkey, adding any remaining marinade to the pan.

Stir the green onion mixture, broccoli florets, and the remaining 1/4 cup of water into the skillet.

Cover and cook for 3 minutes, or until the broccoli is tender-crisp.

Stir the lemon juice mixture again to disperse the cornstarch.

Pour the lemon juice mixture and the cooked turkey into the skillet with the broccoli.

Cook for 2 minutes, stirring constantly, until the sauce thickens and coats the ingredients.

Add more water to thin the sauce if needed.

Serve immediately over rice or noodles.