Make pastry: Pulse flour, sugar and diced cold butter until the mix resembles coarse crumbs. Add the egg yolk and pulse; add 1–2 tsp cold water if the dough seems dry. Turn out, press into a disc, wrap and chill 20 minutes.

Roll & line: On a lightly floured surface, roll the dough to ~3 mm thick. Cut 12 circles and press into tartlet cups or muffin tin, trimming edges. Chill shells 10 minutes. Prick bases lightly. Preheat oven 350°F (175°C).

Blind bake shells: Line each shell with parchment and baking beans (or rice) and blind bake 10–12 minutes, remove beans and bake another 3–5 minutes until pale golden. Remove and cool slightly.

Make salted caramel: In a dry heavy saucepan, heat sugar over medium without stirring (swirl pan) until it melts and reaches a deep amber. Add butter (careful — it will bubble), stir until combined, then remove from heat and whisk in warm cream. Stir in sea salt to taste. Let caramel cool 3–4 minutes (it should still pour but not be too runny).

Assemble & bake briefly: Pour about 1–1½ tbsp caramel into each tart shell, scatter toasted pecans on top, bake 3–4 minutes to set slightly. Cool to room temp, then chill to finish.

Finish: Just before serving, sprinkle a tiny flake of sea salt on each tart for crunch.