Bring a large pot of salted water to a boil. Add the spaghetti and cook according to package directions until al dente. Before draining, reserve 1 cup of the starchy pasta water. Drain the pasta and set aside.

While the pasta cooks, in a medium bowl, toss the cubed eggplant with 2 tablespoons of olive oil, 1/2 tsp salt, and 1/4 tsp black pepper until evenly coated.

Heat a large skillet over medium-high heat. Add the seasoned eggplant in a single layer (work in batches if necessary to avoid overcrowding, which steams rather than fries). Cook for 5-7 minutes, turning occasionally, until the eggplant pieces are golden brown, tender, and slightly caramelized. Remove the cooked eggplant from the skillet and set aside.

In the same skillet (no need to clean), reduce the heat to medium. Add the remaining 2 tablespoons of olive oil and the minced garlic. Sauté for 1 minute until fragrant, being careful not to burn the garlic.

Add the halved cherry tomatoes and red pepper flakes (if using) to the skillet. Cook for 5-7 minutes, stirring occasionally, until the tomatoes begin to burst, soften, and release their juices.

Pour in the vegetable broth (or about 1/2 cup of the reserved pasta water). Bring the sauce to a gentle simmer, using the back of a spoon or a potato masher to gently mash some of the tomatoes and create a more cohesive sauce.

Return the cooked eggplant to the skillet with the tomato sauce. Stir in the chopped fresh basil. Taste the sauce and adjust seasoning with additional salt and pepper as needed.

Add the drained pasta directly to the skillet with the eggplant and tomato sauce. Toss thoroughly to coat all the pasta. If the sauce seems too thick, add a splash more reserved pasta water, a tablespoon at a time, until it reaches your desired consistency.

Serve immediately in bowls, garnished with grated Parmesan cheese and fresh basil leaves, if desired.