Preheat oven to 220°C / 430°F (200°C fan).

Line three trays: Line three large trays with baking / parchment paper.

Brush eggplant with oil: Brush eggplant slices on each side with oil.

Bake 35 minutes: Arrange eggplant in a single layer on the trays and bake for about 35 - 45 mins or until browning and tender, turning the eggplant halfway. I put the trays on the top shelf, in the middle, then I put one tray on the floor of the oven. As each tray finishes, I remove the tray and move the others up.

Cool: Remove from oven, leave on trays to cool.

Sauté onions and garlic: Heat olive oil in a large skillet over medium-high heat. Sauté onions and garlic for 3 minutes until softened and just about to colour on the edges.

Add remaining ingredients: Pour in the passata, canned tomatoes, water, oregano and sugar. Stir and bring to a simmer.

Simmer 30 minutes: Simmer uncovered for about 30 - 40 minutes, stirring occasionally, until thickened, adding the basil stalks halfway through cooking (so they don’t lose their flavour).

The final consistency should be slightly thicker than a pasta sauce so it’s spreadable and not leaching liquid, but not too pasty either. Add extra water a little at a time if required during cooking if it gets too thick. Remove the basil stalks and discard.

Season: Stir in salt and pepper. (Remember, we get salt from the parmesan too, so no need to go overboard here)

Reduce oven to 180°C / 350°F (160°C fan).

Smear a little tomato sauce in the bottom of baking dish, 23 x 33cm / 9 x 13" (or thereabouts).

Layer 1: Lay one third of the eggplant so it covers the base (some overlap is OK when layering eggplant). Spread 1/3 of the remaining sugo over eggplant. Drizzle with a little olive oil. Sprinkle with 1/3 of the parmesan, and 1/3 of basil leaves.

Layer 2: Repeat another 1/3 each of eggplant, tomato sauce, olive oil, basil and parmesan.

Layer 3 (top layer): Repeat again with remaining eggplant, tomato sauce and some olive oil. Do not put basil on top layer (we will garnish after baking). Scatter with remaining parmesan, then all the mozzarella.

Bake for 25 mins until bubbling and golden.

Rest: Let it rest for 5 to 10 minutes (easier to slice neatly). Scatter over remaining fresh basil leaves. Cut like lasagna and serve! (Optional: sprinkle with extra parmesan).