Bake pecans in a single layer in a shallow pan at 350° for 8 to 10 minutes or until toasted and fragrant, stirring once. Cool 10 minutes. Process pecans, syrup, cream of coconut, cinnamon, vanilla, and kosher salt in a food processor 30 to 60 seconds or until smooth. With processor running, pour water through food chute. Press mixture through a fine wire-mesh strainer into a pitcher, using back of spoon. Discard solids. Cover and chill 3 to 24 hours. Stir in milk and bourbon just before serving. Serve over ice. Garnish, if desired.