Slice the 3 berenjenas grandes cortadas en rodajas de 1/2 pulgada into 1/2-inch rounds. Lay them in a single layer on a baking sheet or in a colander, sprinkle generously with 2 tsp sal kosher on both sides, and let them sit for 20–30 minutes. This draws out moisture and bitterness. Pat very dry with paper towels.

Preheat your oven to 425°F. Arrange the dried 3 berenjenas grandes cortadas en rodajas de 1/2 pulgada slices in a single layer across two lightly oiled baking sheets. Brush both sides of each slice with 3 tbsp aceite de oliva. Roast for 20–25 minutes, flipping once halfway through, until golden and tender. Set aside. Reduce oven temperature to 375°F.

Heat 2 tablespoons of aceite de oliva in a large skillet over medium-high heat. Add the diced cebolla amarilla grande and cook, stirring occasionally, for 5–6 minutes until softened and lightly golden. Add the 4 dientes de ajo picados and cook for 1 more minute until fragrant.

Add the 1 ½ lb cordero molido o sustituir carne molida de res to the skillet. Break it up with a wooden spoon and cook over high heat for 6–8 minutes until browned and cooked through. Drain off any excess fat if needed.

Add the 2 tbsp pasta de tomate and stir to coat the meat. Cook for 1–2 minutes until it darkens slightly. Pour in the ½ cup vino tinto (if using) and let it bubble and reduce for 2 minutes. Add the 1 lata de tomates triturados, 1 tsp canela molida, ½ tsp pimienta gorda molida, ¼ tsp nuez moscada molida, ½ tsp orégano seco, 2 tsp sal kosher, and ½ tsp pimienta negra. Stir well to combine.

Reduce the heat to medium-low and simmer the sauce uncovered for 20–25 minutes, stirring occasionally, until it is thick and most of the liquid has evaporated. The sauce should not be watery — this is key to a firm moussaka. Taste and adjust seasoning. Set aside.

Melt the 4 tbsp mantequilla sin sal in a medium saucepan over medium heat. Add the 4 tbsp harina de trigo all at once and whisk constantly for 1–2 minutes to cook out the raw flour taste — it should smell nutty and look pale golden.

Slowly pour in the 2 ½ cups leche entera, a little at a time, whisking constantly after each addition to prevent lumps. Once all the leche entera is incorporated, continue to cook, whisking frequently, for 4–5 minutes until the sauce is thick enough to coat the back of a spoon.

Remove the pan from the heat. Stir in the ¼ tsp nuez moscada molida, 2 tsp sal kosher, and ¼ tsp pimienta blanca. Let the sauce cool for 3–4 minutes — it should no longer be steaming. Beat the 2 huevos batidos in a small mixing bowl, then whisk them briskly into the béchamel. Stir in half of the queso Parmesano. The sauce should be smooth, thick, and glossy.

Lightly grease a baking dish (9x13-inch). Arrange half of the roasted 3 berenjenas grandes cortadas en rodajas de 1/2 pulgada slices in an even layer across the bottom, overlapping slightly if needed. Spread all of the meat sauce evenly over the 3 berenjenas grandes cortadas en rodajas de 1/2 pulgada layer.

Layer the remaining berenjenas grandes cortadas en rodajas de 1/2 pulgada slices over the meat sauce. Pour the béchamel evenly over the top, spreading it to the edges with a spatula. Sprinkle the remaining queso Parmesano over the surface.

Bake at 375°F for 40–45 minutes, until the top is deep golden brown and the béchamel is set (it should not jiggle when you shake the dish). If the top is browning too fast, loosely tent with aluminum foil.

Remove from the oven and let the moussaka rest for at least 20–30 minutes before cutting. This resting time is essential — it allows the layers to firm up so you get clean, beautiful slices. Serve warm.