Butter tarts can be made with a simple recipe cooking butter, brown sugar, eggs and maple syrup in a pastry shell. This recipe calls for pecans, but raisins or walnuts can be used instead.
To make crust combine 2 ¼ cup pastry flour with 1/3 teaspoon salt. Using a pastry cutter, cut in 1 cup unsalted butter. Add 1 tablespoon lemon juice or vinegar to 6 tablespoons cold water, and mix into the dough. Divide the dough into two cylinders and chill for two hours.
Remove the pastry 20 minute before it is to be used. Preheat oven to 400 degrees Fahrenheit. Take a 12 cup muffin tin and lightly grease it.
Cut each pastry cylinder into six pieces. Flour the work surface, and roll the pastry pieces out to about ¼ inch thick. Trim them with a 4 ½ inch cookie cutter, and push them into the muffin tin. They should stick out about ½ inch over the sides of the muffin cups. Put them in the refrigerator.
Prepare the filling by melting ½ cup butter and 1 cup brown sugar in a saucepan. Stir over medium heat until bubbling. Remove from heat. Whisk 2 large eggs, ½ cup maple syrup, 1 tablespoon lemon juice, 1 teaspoon vanilla extract and ¼ teaspoon salt in a separate bowl. Add this to the brown sugar mixture, whisking in to ensure it is mixed.
Place a few toasted pecan pieces into each cup, and distribute the filling on top of the pecans. Bake for 10 minutes at 400 degrees Fahrenheit, then an additional 10 to 15 minutes at 375 degrees. They are ready to take out of the oven when the edges have browned and the filling is bubbling. After cooling for 5 minutes, twist each tart in the pan to make them easy to remove. Let them cool completely in the pan.