To make the cookies:
Line a 9- x 5-inch loaf pan with plastic wrap, allowing enough to extend over the edges of pan so they can cover the dough for refrigerating. Set aside.
Position knife blade in food processor bowl; add dates, orange zest and orange juice. Process 45 seconds, or until dates are finely chopped.
In a medium bowl, beat butter at medium speed until fluffy. Gradually add sugar, beating until well blended.
Add the egg and vanilla; beat well.
In a separate bowl, combine flour, baking powder and salt. Whisk together to combine.
Gradually add flour mixture into the butter mixture, beating at low speed until blended.
Divide the dough into 3 portions. Knead 1/2 cup of the pecans into 1 portion of dough; press this portion into prepared pan.
Knead the date mixture into 1 portion of dough; press in pan over pecan dough.
Knead remaining 1/2 cup pecans into remaining dough; press into pan over date dough.
Cover and chill at least 2 hours or freeze up to 1 month. (If freezing, defrost again in refrigerator for 2 days before making cookies.)
Preheat oven to 350F degrees.
Invert loaf pan onto a cutting board; remove and discard plastic wrap. Cut dough lengthwise into 3 lengthwise logs. Cut each log of dough crosswise into 1/4-inch thick slices. Place the slices 1-inch apart on parchment lined baking sheets. (Each log yields about 20 cookies)
Bake for 10-11 minutes until still soft and NOT brown at edges (I like these a little more chewy, but if you want them as tea or coffee dunking cookies, bake an additional 2 minutes until the edges are browned).
Cool slightly on baking sheets; remove to wire rack to cool completely.
To make the glaze:
In a small bowl, mix orange zest and juice. Whisk in 1/2 cup confectioners sugar and add more for thicker glaze.
Using a spoon, drizzle a stripe or droplets over each cookie. Let sit for about 10 minutes to let glaze harden slightly for packaging or serving.
These cookies ship well as they taste even better two or three days after baking.