#### **Step 1: Prepare the Pastry**
In a bowl, mix **flour and salt**. Cut in **cold butter** using a pastry cutter or food processor until crumbly.
Gradually add **ice water**, one tablespoon at a time, mixing until the dough comes together.
Form into a **disc, wrap in plastic wrap**, and chill for **30 minutes**.
#### **Step 2: Roll & Cut the Pastry**
Preheat oven to **375°F (190°C)**.
Roll out the dough on a lightly floured surface to **1/8-inch thickness**.
Cut into **3-inch circles** and press into a muffin tin. Chill while making the filling.
#### **Step 3: Make the Filling**
In a bowl, whisk together **melted butter, brown sugar, corn syrup, egg, vanilla, vinegar, and salt** until smooth.
Stir in **raisins or nuts**, if using.
#### **Step 4: Assemble & Bake**
Fill each tart shell **2/3 full** with the filling.
Bake for **18-22 minutes**, until the filling is set but still slightly soft in the center.
Let cool in the pan for **5 minutes**, then transfer to a rack.