- Coat lamb with mixture of 1 Tbsp. stir-fry sauce and 1/2 teaspoon garlic; let stand 30 minutes.
- Meanwhile, pare eggplant lengthwise to form strips, then cut into matchsticks.
- Heat 1 Tbsp. oil in hot wok or large skillet over high heat. Add lamb and stir-fry 1 minute; remove.
- Heat 2 Tbsp. oil in same pan; reduce heat to medium-high. Add remaining 1 teaspoon garlic; stir-fry 10 seconds. Add eggplant and salt; stir-fry 6 minutes. Push eggplant to edge of pan; add remaining 1 Tbsp. oil, onion, bell pepper and squash; stir-fry with eggplant 5 minutes.
- Pour in 1/3 cup stir-fry sauce with red pepper and cook, stirring constantly, 2 minutes longer. Stir in lamb; heat through.