Preheat the oven to 350ºF. Line your cookie sheets with parchment or lightly grease them.
In a small bowl, rub the lemon zest and sugar together with your fingers, to release the oils and infuse the sugar.
In a large bowl, cream the softened butter with the lemon-infused sugar until light and fluffy.
Add the egg and lemon juice; beat until well combined.
In a separate bowl, whisk together the flour, baking powder, and salt.
Add the dry ingredients to the butter mixture, mixing until just combined.
Stir in the toasted chopped pecans.
Divide the dough in half and shape each half into a log about 2 inches in diameter.
(Optional) Roll each log in additional chopped pecans for a decorative edge.
Wrap each log tightly in parchment, waxed paper, or plastic wrap.
Chill in the refrigerator for at least 2 hours, or until very firm. You can also freeze the logs to speed up the process, or store them in the freezer to bake up whenever you have a craving—the dough slices and bakes really well straight from the freezer.
Slice the logs into ¼-inch-thick rounds and place on the prepared cookie sheets. (These cookies do not spread.)
(Optional) Sprinkle tops with sugar for a sparkly finish.
Bake for 8-10 minutes, or until cookies are firm to the touch and lightly golden on the bottom.
Cool on the pan for a few minutes, then transfer to a wire rack.
Store in an airtight container. They can be stored on the counter but last longer if stored in the fridge or freezer.