Position the racks in the top and lower third of the oven and preheat to 350 degrees F.
In a large bowl, whisk together the flour, baking soda, salt, allspice, cinnamon, and mace.
In another large bowl, combine the butter and sugar and, with a hand-held electric mixer, mix on low speed until just incorporated. Raise the speed to high and mix until light and fluffy. (Occasionally turn the mixer off, and scrape the sides of the bowl down with a rubber spatula.)
Add the brown sugar and mix until incorporated. Add the eggs to the butter mixture, one at time, waiting for the first one to be fully incorporated before adding the last. Mix in the vanilla.
Reduce the mixer's speed to low. Add the flour mixture, little by little, until a smooth dough is formed (scrape the bowl down occasionally). Turn off the machine, stir in the oats, raisins, and pecans with a rubber spatula.
Line 2 baking sheets with parchment paper. Using a spoon, drop heaping tablespoons of the dough onto the sheets, spaced about 2 inches apart.
Bake the cookies in batches, turning the pans once, until golden brown, but still soft and spongy, about 15 minutes per batch. Let the cookies cool slightly on the baking sheets, and then transfer to racks to cool completely. Store in a sealed container.