Heat olive oil over medium-high heat and add eggplant, stirring to coat. Cook for 3-4 minutes, until eggplant just starts to color. Add garlic and ras al hanout, and cook 30 seconds, or until just fragrant. Stir in tomatoes, salt and pepper, and lower heat to medium-low. Simmer, uncovered, for 30-40 minutes, stirring occasionally, until everything has “melted” into a sort of chunky jam-like consistency. Season with additional salt and pepper, if you like, and stir in basil leaves.