Heat 1 tablespoon olive oil in a large skillet over medium-high heat.
Add beef and cook for 3–4 minutes until browned. Remove from skillet and set aside.
Add remaining olive oil and eggplant to the skillet.
Cook eggplant for 5–7 minutes, stirring occasionally, until tender and lightly caramelized.
Add garlic and cook for 30 seconds until fragrant.
Stir in soy sauce, sesame oil, black pepper, red pepper flakes, and water.
Return beef to the skillet and toss to coat in the garlic sauce.
Cook for 2–3 minutes until everything is heated through and glossy.
Remove from heat and serve immediately.