1. Preheat a conventional oven to 350 degrees, or a convection oven to 325 degrees, arranging the oven racks so they divide the oven into thirds.
2. Line mini-muffin pans with mini cupcake liners.
3. Beat the Plugrá Butter and cream cheese together on medium high speed for about 2 minutes, until very fluffy and creamy.
4. Add the flour and blend on low speed for about 30 seconds. Using two teaspoons of dough, scoop the dough into 48 pieces, placing one piece into each lined mini muffin cup.
5. Using floured fingers, press the dough gently to line the bottom and sides of the cupcake liners, being sure not to make a hole in the bottom of the dough.
6. Make the filling: Melt the butter. Mix all of the filling ingredients, stirring with a wooden spoon until they are evenly blended.
7. Spoon the filling into each dough-lined muffin cup, being sure you get plenty of nuts and chips in each cup, and that you have also included some of the syrupy liquid.
8. Occasionally stir the filling while you are doing this.
9. Place the filled muffin tins into the preheated oven, and bake for 30-35 minutes, rotating the pans halfway through the baking time. When they are done, the dough will be golden brown and the filling will have formed a crust.
10. Remove the pans from the oven and set them on wire racks to cool. After 10 minutes, carefully turn the mini tarts out of the baking pans, and set the tarts upright on the wire racks to finish cooling. Store the completely cooled tarts in an airtight container for up to 2 weeks.