Slice the aubergines into 5 mm (about 1/5 in) rounds. Lay slices on a tray, sprinkle both sides with 1 tbs salt, and let them sweat for 20–30 minutes to remove bitterness and excess moisture. After sweating, rinse the slices under cold water and pat dry thoroughly with paper towels.

Cook aubergine (two options)

Option A — Roast: Preheat oven to 220°C (425°F). Toss slices lightly with 2 tbs olive oil, arrange in a single layer on a baking sheet lined with parchment, roast 12–15 minutes turning once until golden and tender. Option B — Pan-fry (crisper): Heat 1–2 tbs olive oil in a large skillet over medium-high heat. If using breading, follow the breading steps below and fry 2–3 minutes per side until golden. If not breading, fry plain slices 2–3 minutes per side until golden and soft. Transfer cooked aubergine to a paper-towel lined tray to drain.

Breading (optional for aubergine)

Assemble breading station

Place flour in one shallow dish, beaten egg in another, and breadcrumbs mixed with parsley, 0.25 tsp salt and 0.25 tsp pepper in a third.

Dredge each rinsed, dried aubergine slice first in flour (shake off excess), then in beaten egg, then press evenly into the breadcrumb mixture. Fry as directed above in the Aubergine section (Option B).

Tomato Sauce

Make sauce

In a medium saucepan, heat 1 tbs extra virgin olive oil over medium heat. Add the minced garlic and chopped shallot and cook until softened and fragrant, about 2–3 minutes, taking care not to brown the garlic. Stir in tomato paste and cook 30 seconds. Add crushed tomatoes, dried oregano, 1 tsp salt, 1/2 tsp black pepper and 1 tsp sugar (if using). Bring to a gentle simmer, reduce heat to low and cook, uncovered, for 12–15 minutes until slightly thickened. Stir in chopped fresh basil at the end and remove from heat. Taste and adjust seasoning.

Cheeses

Slice or tear the fresh mozzarella into pieces roughly the size of the croissant interior. If using ricotta, stir it lightly with 1–2 tbs of the tomato sauce and 1 tbs grated Parmesan to season, producing a spreadable ricotta filling.

Croissants Assembly & Baking

Prepare croissants

Preheat oven to 190°C (375°F). If croissants are very fresh or soft, you can warm them briefly in the oven for 3–4 minutes to make them easier to slice without tearing. Using a serrated knife, slice each croissant horizontally but not all the way through, creating a hinge, or slice fully in two depending on desired presentation.

Assemble Aubergine Parmigiana Croissants

Open each croissant. Spread about 1–2 tbs of tomato sauce on the bottom half, then place 2–3 roasted/pan-fried aubergine slices (trim to fit if necessary). Add a spoonful (about 1 tbs) of ricotta mixture if using, then a few pieces of fresh mozzarella (about 30–35 g per croissant). Spoon another 1 tbs of sauce over the cheese, sprinkle with 5–6 g grated Parmesan and a small basil leaf. Close the croissant.

Finish and bake

Brush the outside of each assembled croissant with melted butter. Place croissants on a baking sheet lined with parchment. Bake in the preheated 190°C (375°F) oven for 8–10 minutes, until cheese inside is melted and croissant is warmed through and slightly crisp. If you prefer more browning on top, switch to broil/grill for the last 1–2 minutes, watching carefully to avoid burning.

Finishing & Garnish

Remove croissants from the oven, let rest 2 minutes. Garnish each with additional grated Parmesan and torn fresh basil leaves. Serve warm.