Preheat oven to 375 degrees F (190 degrees C). Spray 12 muffin cups with cooking spray.
Stir graham cracker crumbs and white sugar together in a bowl; stir in melted butter until crumbs are coated. Press crumb mixture evenly into the bottom and partway up sides of prepared muffin cups.
Bake shells in the preheated oven for 5 minutes. Remove shells from oven and keep oven at 375 degrees F (190 degrees C).
Beat brown sugar and softened butter together in a bowl until smooth and creamy, about 2 minutes. Beat eggs into sugar mixture, adding one at a time and beating until fully incorporated before adding next; beat in vanilla extract. Stir half-and-half into sugar mixture.
Place a spoonful of raisins and pecans into the bottom of each shell; pour about 1/4 cup sugar mixture into each shell.
Bake tarts in the preheated oven until bubbly, about 15 minutes. Remove tarts from oven and cool completely on a wire rack, about 15 minutes.
