In a medium bowl, combine the graham cracker crumbs and shredded coconut. Pour in the melted butter and mix until the crumbs are evenly coated.
Press the crumb mixture firmly into the bottom of a greased 9x9 inch baking dish to form a crust. Use the back of a measuring cup to smooth it out. Place it in the refrigerator to chill while you prepare the filling.
In a large mixing bowl, whisk together the sweetened condensed milk, fresh lemon juice, lemon zest, and vanilla extract until well combined.
In a separate bowl, whip the heavy cream with an electric mixer until soft peaks form. Gradually add the powdered sugar and continue whipping until stiff peaks form.
Gently fold the whipped cream into the lemon mixture until fully incorporated, being careful not to deflate the whipped cream.
Pour the lemon filling over the chilled crust, spreading it evenly. Cover and refrigerate for at least 4 hours, or until set.
Once set, cut into bars and serve chilled.
Notes
Serve the bars on a platter, garnished with fresh mint leaves and thin lemon slices for an extra pop of color and freshness.