Ingredients :

• Mascarpone (250 g) — Use full-fat mascarpone, not low-fat. The low-fat version doesn’t firm up well during baking, and you’ll end up with a sagging filling. The Galbani brand is reliable and easy to find. Leave it at room temperature for an hour before incorporating — it blends much better.
• Yellow lemons (2 pieces) — Must be fresh. Bottled juice has a flat, chemical taste that shows immediately in the result. If you can find them, Sicilian or Amalfi lemons have a floral, intense fragrance that no industrial lemon can replicate. Otherwise, organic lemons with a nice thick skin. You use the zest too, so the skin matters.
• Shortcrust pastry — Store-bought works very well here. Choose ‘pure butter’ — not margarine. Blind-bake it for 10 minutes before pouring in the cream: this prevents a soggy bottom and gives you a base that slightly cracks under the tooth, a contrast in textures that makes all the difference.
• Cornstarch (1 tbsp) — Marked optional in the ingredients list. In practice, it helps the cream hold its shape better when cutting, so the first slice doesn’t collapse. When hosting guests, use it.