Using an electric mixer, cream butter and both sugars together in a large bowl, until light and fluffy; about 3 minutes. Crack eggs into a measuring cup and beat in 1 at a time.
In a mixing bowl, whisk together flour, salt, baking powder, baking soda, cinnamon, and allspice. Gradually add large spoonfuls of the dry mixture into the creamed mixture. Once incorporated, fold in raisins, pecans, and oats with a rubber spatula.
Add a small ice cream scoop of dough (about 2 inches in diameter), onto parchment paper lined cookie sheets, spacing about 1-inch apart. Pat top down slightly and bake in the preheated oven for 12 minutes. Remove to wire rack to cool completely for 45 minutes before making sandwiches.
Remove ice cream from the freezer and allow to soften.
Turn 6 cookies face side up on counter. Scoop 1/2-cup of ice cream on the cookies and using an offset spatula, spread evenly to the edges. Top ice cream with a second cookie and press down to adhere. Roll ice cream edges in the chopped pecans. Freeze for 2 hours or until solid.