Heat vegetable oil in a large skillet or wok over medium-high heat.
Add ground turkey and cook until browned and cooked through, about 5-7 minutes. Season with salt and pepper.
Remove turkey from the skillet and set aside.
In the same skillet, add garlic and ginger; sauté for 30 seconds until fragrant.
Add onion, bell pepper, broccoli, and carrot; stir-fry for 4-5 minutes until vegetables are tender-crisp.
Return the cooked turkey to the skillet and stir to combine.
Pour in soy sauce, hoisin sauce, and sesame oil; stir well.
Add the cornstarch slurry to the skillet and cook for another 1-2 minutes until the sauce thickens.
Remove from heat and garnish with chopped green onions and sesame seeds if desired.
Serve hot over steamed rice or noodles.