Canadian Butter Tart Bars with a Shortbread Crust

Preheat oven to 350°F (175°C). Grease and line an 8x8 inch baking pan with parchment paper, leaving an overhang for easy removal.

Prepare the shortbread crust: In a large bowl, whisk together the flour, powdered sugar, and salt. Cut in the cold butter using a pastry blender or your fingers until the mixture resembles coarse crumbs.

Press the mixture firmly into the prepared baking pan. Bake for 15-20 minutes, or until lightly golden.

While the crust is baking, prepare the butter tart filling: In a medium bowl, whisk together the melted butter, brown sugar, egg, corn syrup, vanilla extract, vinegar, and salt until smooth.

If using, stir in the raisins.

Pour the butter tart filling evenly over the partially baked shortbread crust.

Return the pan to the oven and bake for another 15-20 minutes, or until the filling is set around the edges but still slightly gooey in the center.

Let the bars cool completely in the pan before lifting them out using the parchment paper overhang. Cut into bars and serve.