1. Preheat oven to 300 degrees. Sift together flour and salt into a medium bowl. Beat butter with a mixer on medium-high speed until fluffy, 3 to 5 minutes, scraping down sides of bowl with a rubber spatula as needed. Add sugar gradually, beating between additions; continue to beat until mixture is very pale, about 2 minutes total. Reduce speed to low, and add flour mixture; beat until just combined.

2. Mix in coconut and pecans. Press dough evenly into a buttered 10-inch springform pan; refrigerate until firm, about 20 minutes. Cut dough into 8 wedges. Evenly pierce all over with a skewer.

3. Bake until shortbread is firm in center and golden brown, about 1 hour 10 minutes. Transfer pan to a wire rack; immediately recut wedges with a paring knife. Let cool completely in pan.