Step 1: Pate Brisee
(I should mention that many of these pictures for the crust dough are reused from another of my instructables, Night Sky Blueberry Pie, as the ingredients and steps are all the same except doubled. Even when only one 9" crust is needed, I still used the doubled amount, so I have another crust on standby in the refrigerator or freezer.)
1 1/4 cups all-purpose flour
1/2 tsp. salt
1 Tbsp. granulated white sugar
1/2 cup unsalted butter, cold and cut into small pieces
1/8 - 1/4 cup ice water
Combine flour, sugar and salt in a food processor (or bowl, if that is what you have to work with). Add butter and pulse to combine until resembles course crumbs, about 10 to 15 seconds (if using bowl, cut the butter in with a pastry blender). Add ice water in a steady stream, starting with just 1/4 cup. Process just until the dough pinches together (crumbs about the size of peas now). If necessary add a little more water until you get to this state. You should not need more than 1/2 cup nor require longer than 30 seconds processing.
Shape the dough into a flattened disc, wrap into plastic wrap and refrigerate for 1 hour. (The dough can be frozen for up to a month; thaw overnight in the refrigerator before using.
Take the disc and roll it out onto your floured work surface until about 12" in diameter. Roll from the center out and rotate your crust quarter turns occasionally to avoid sticking. Using a 4" circle-shaped cookie cutter, cut out 12 pieces of dough and transfer each to a muffin pan. You can re-roll out your scrap dough if you are short, but avoid it if you can, as over-worked dough results in toughness. Refrigerate for at least 30 minutes.
Step 2: The Butter Filling
1/3 cup unsalted butter, softened
1/2 cup packed light brown sugar
1/2 cup golden syrup OR light corn syrup OR maple syrup OR packed light brown sugar again (this latter choice will make the tart filling less runny--a characteristic desired by some and not by others)
1 tsp. pure vanilla extract
2 Tbsp. heavy whipping cream
Optional: 1/2 cup raisins OR pecans, toasted and chopped OR walnuts, toasted and chopped (I nixed these options because of picky eaters.)
Preheat the oven to 375 degrees Fahrenheit.
If you are using raisins and want a runny filling, plump the raisins by submerging them in a bowl of very hot tap water for 10 - 15 minutes. Drain before adding.
In a medium-sized mixing bowl, cream all brown sugar and butter. In a separate medium-sized mixing bowl, add the syrup and place in a hot water bath by putting the bowl inside a larger bowl with a shallow pool of hot tap water. In this same bowl with the syrup, whisk the eggs and vanilla extract, and then stir in the cream. Add the liquid mixture to the creamed butter and brown sugar and stir to combine. Stir in raisins or nuts.
Remove the crust-lined muffin pan from the refrigerator and spoon in about 2/3 - 3/4 full with the filling. Bake in the oven for 15 - 20 minutes. Center should be inflated (will deflate once cooled) and edges bubbly.
Serve warm or cool, and enjoy!