Preheat oven to 350 degrees and line baking sheets with parchment paper.
In a medium bowl, cream butter and sugars together until smooth.
Add sea salt, baking soda, and water and stir.
Add egg and mix to combine.
Add vanilla extract.
Add flour, half at a time, and stir until just combined.
Fold in finely chopped pecans and stir until evenly dispersed.
Using a 1 TBS cookie scoop, scoop the dough onto lined baking sheets 2 inches apart.
Gently press a pecan half into the top of each cookie. Do not over-flatten.
Bake cookies for 12 minutes, rotating halfway through.
Allow cookies to cool on the baking sheet for 5 minutes, prior to transferring to a wire rack to cool completely.
Store in an airtight container for up to 1 week or freeze.