Combine flour, sugar, and salt in a large mixing bowl. Integrate the cold butter using a pastry cutter or fingers until the mixture reaches a crumbly texture, with the butter appearing in pea-sized chunks. Alternatively, a food processor may be used to combine the flour, salt, and sugar, followed by the addition of butter, pulsing until the mixture is crumbly.

Gradually incorporate 2-3 tablespoons of cold water, manipulating the dough until it forms a cohesive ball. Add more ice water if necessary. In a food processor, add water and pulse until the dough begins to form a ball.

Form the dough into a thick disk and envelop it in plastic wrap. Refrigerate for a minimum of one hour or up to one week.

On a large piece of wax paper, roll out the pastry to the desired thickness.

Utilize a circular cookie cutter, a large cup, or a small bowl to cut the dough into rounds of 3.5-4 inches in diameter.

Fit the rounds into a 12-cup muffin pan, gently pressing them into the base and up the sides of each cup. Repair any holes by pressing the pastry together. Subsequently, freeze the pan for 10-15 minutes.

Preheat the oven to 350 degrees Fahrenheit (175 degrees Celsius).

In a large bowl, whisk together the brown sugar, corn syrup, melted butter, eggs, vinegar (if using), and vanilla extract.

Evenly distribute the filling into the unbaked tart shells.

Bake in the preheated oven for 20-25 minutes, or until the pastry is golden brown and the filling has slightly puffed.

Allow the tarts to cool in the pan for 10 minutes before transferring them to a wire cooling rack.

Store the baked butter tarts in a refrigerator for several days or freeze them for up to 3 months.