I've taken my dark malts and ground them the night before. Take a gallon of room temp water and empty and little out of it. Place your ground dark malts in the remaining water and 'steep' overnight.
Brew day strain the grain from the gallon jug and add to brew kettle. Add the remaining grain to the grist once the mash is done.
You'll get great color w/ very little of the 'dark' roasty flavors.