Preheat oven to 350 degrees F.
Place flour, salt, softened butter, powdered sugar, and vanilla in a bowl and beat together until combined. Mixture will look like crumbs at first, but continue beating and it will come together into a thick dough.
Scoop out dough by tablespoons and roll into balls. Place on a lined cookie sheet and flatten each dough ball until it's about 1.5 inches in diameter.
Bake for 12 minutes, until edges feel set. Meanwhile, unwrap the Rolos.
Remove the cookies from the oven and top each one with one Rolo in the center. Return to the oven for 90 seconds, then remove and push a pecan down into each Rolo. Sprinkle with sea salt if desired.
Cool completely before serving.