Preheat the oven to 375 degrees.
Melt the coconut oil, and let it cool to room temperature.
In the bowl of a stand mixer, mix the cooled coconut oil, sugar, egg, and vanilla extract until well-combined.
In a separate bowl, stir together the flour, baking soda, and cream of tartar. Add this dry mixture to the wet ingredients a little bit at a time, alternating with the milk. Start and end with a portion of the dry ingredients (i.e. dry, milk, dry, milk, dry). Form the dough into two balls. Wrap each ball in a piece of wax paper and refrigerate briefly while you prepare the filling ingredients. (If you refrigerate it for too long, the coconut oil will solidify and the dough will become too hard to handle.)
To make the filling, combine the raisins, crushed pineapple, and sugar in a small saucepan. Bring to a slight boil. While this mixture is heating up, stir together the starch and the water in a small bowl. Add it to the boiling filling mixture, and stir to thicken. You’ll need to stir the lightly boiling mixture for a minute or two until it’s no longer runny.
Remove the dough from the refrigerator and roll it out to about 1/8 inch thickness (as thin as possible) on a well-floured surface. Cut out 3-inch circles of dough using a cookie cutter or a glass.
Put 9 circles of dough on a cookie sheet, and place about two teaspoons of filling in the middle of each circle. Then place another circle on top of the filling and press down the edges.
Bake for 10 to 12 minutes, until lightly browned.