Grana Padano and Caramelized Onion Tartlet

Method

1. For the pastry: in a stand mixer with paddle attachment, combine 300 g soft butter and 500 g weak flour on low speed until sandy.
2. Add 150 g grated Grana Padano, one beaten egg, a pinch each of salt and pepper, and sugar of choice (about 100 g recommended but adjust to taste). Mix just until dough comes together.
3. Gently compact the dough into a disc, wrap in plastic, and refrigerate for at least 2–3 hours (preferably overnight).
4. For the caramelized onion: melt butter in a pan over low heat, add sliced white onions, a pinch of salt, a pinch of sugar, and a bay leaf. Cook slowly until deeply caramelized.
5. At the end, add 1–2 tablespoons of vinegar to balance sweetness. Keep aside.
6. Preheat oven to 150-160°C (300-320°F).
7. Roll out the chilled dough to 3 mm thickness on a lightly floured surface. Cut strips to line a micro-perforated tartlet mold (or use standard tartlet tins). Prick the base with a fork.
8. Bake the pastry shells for about 15 minutes, until golden and firm. Let cool completely.
9. For the mousse: heat cream in a small pot, add 100 g grated Grana Padano and stir until melted. Strain to remove any lumps, then spread on a tray to cool.
10. Once the Grana mixture is cold, fold in an equal amount of mascarpone and a little semi-whipped cream. Adjust seasoning with salt and pepper.
11. To assemble: spoon a layer of caramelized onion into each pastry shell, pipe the mousse on top, and smooth with a spatula.
12. Decorate with pieces of pickled red onion (agrodolce), walnuts, and fresh thyme leaves. Serve at room temperature.