A Canadian staple, the butter tart square has earned annual holiday cookie tin status in many households. They are easier to make than individual tarts, yet they retain the sweet maple creaminess we have come to expect from this dessert.
Makes one 8″ (20cm) square pan, 25 – 36 squares.
Preheat the oven to 350°F (180°C). Lightly grease and line the bottom and sides of an 8-inch (20 cm) square pan with parchment paper.
For the base, stir the flour, oats and brown sugar by hand in a large bowl. Add the melted butter and stir together until the mixture is rough and crumbly (like a fruit crisp topping).
Press into the bottom of the pan, bake for 12 minutes to set (it will not brown) and then let cool in the pan on a wire rack. Leave the oven on. While the base is cooling, prepare the topping.
For the topping, whisk the brown sugar, maple syrup and eggs together until combined. Whisk in the melted butter followed by the vinegar, vanilla and salt.
Sprinkle the raisins (or pecans) (if using) in an even layer over the bottom of the base and carefully pour the maple syrup mixture over-top (you can move the raisins or pecans around to realign them, if required).
Bake for 25 to 30 minutes, until the topping bubbles just around the edges and is set when the pan is gently jiggled. Let cool completely in the pan on a wire rack before cutting into squares.