Butter Tart

Method

1. mix5 min
   crumbly dough that just holds together
   Cut cold butter into flour and salt, then add ice water only until the dough holds when squeezed. Extra water and kneading develop gluten and make the small shells tough.
2. rest30 min
   dough chilled and relaxed
   Flatten, wrap and chill the dough. Resting keeps the butter cold and relaxes gluten so the shells do not shrink away from the tin.
3. mix2 min
   glossy filling
   Whisk brown sugar, melted butter, egg, maple syrup and vanilla just until smooth. Avoid whipping in excess air; the filling should bake dense and gooey rather than foamy.
4. assemble10 min
   shells two-thirds full
   Roll and cut pastry into muffin-tin shells, add raisins if using, and fill only about two-thirds full. Overfilling guarantees boil-over as the sugar mixture bubbles.
5. bake18 min
   400°F / 205°C, pastry golden and centers still slightly mobile
   Bake until the crust is golden and the filling edges are set while the centers still jiggle slightly. Carryover heat finishes the custard-like set; baking until rigid loses the characteristic gooey center.