1) Salt the eggplant
Heat oven to 425°F. Lay eggplant slices on sheet pans in a mostly single layer. A little edge-to-edge snugness is fine, but avoid stacking or heavy overlap. Sprinkle with 2 teaspoons kosher salt. Let sit 15 minutes (this helps), then pat dry with paper towels.
2) Roast until tender and golden
Brush or drizzle eggplant with olive oil on both sides, using enough to lightly coat. Roast 18 to 22 minutes, flipping halfway, until tender with golden edges. The slices should bend easily with no firm, raw center. If your pans are crowded, roast in batches or add a few minutes and rotate the pans for even browning.
If the eggplant looks wet on top after roasting, let it cool for 5 minutes, then blot lightly with paper towels.
3) Mix the ricotta layer
In a bowl, stir together ricotta, 1/2 cup Parmesan, garlic, herbs (if using), salt, pepper, and red pepper flakes. Taste and adjust the seasoning. Then stir in the egg until combined. (If you prefer not to taste dairy straight from the bowl, you can skip tasting, or cook a tiny dab in a skillet to check seasoning.)
4) Assemble the layers
Lower oven to 375°F. Spread about 3/4 cup marinara in the bottom of a 9x13-inch baking dish.
Aim for 3 eggplant layers total (sometimes 4 if your slices are small). For each layer, add:
- Eggplant (a snug single layer)
- Marinara (about 1 cup)
- Ricotta mixture (about 1/3 of the mixture, dropped in spoonfuls, then gently spread)
- Mozzarella (about 1/2 cup)
- Parmesan (about 2 to 3 tablespoons)
Repeat until you are out of eggplant and ricotta. Finish with sauce, then a generous layer of mozzarella and Parmesan on top (use the remaining cheese).
5) Bake, then rest
Cover with foil (tent it slightly so it does not stick to the cheese). Bake 25 minutes. Uncover and bake 20 to 25 minutes more, until bubbling and browned on top.
Let rest 10 to 15 minutes before slicing. Top with basil if you want to feel fancy with minimal effort.
