Add 6 large egg yolks and 2 large whole eggs to second mixing bowl. Whisk vigorously until yolks and whole eggs are combined, approximately 5 seconds.
Add ½ cup maple syrup to egg mixture and whisk until ingredients are just combined.
Add ⅔ cup freshly squeezed lime juice and zest from 2 large limes to egg mixture. Whisk until fully incorporated.
Transfer egg mixture to heavy saucepan and place on stovetop over medium-low heat.
Add 4 tablespoons ghee to saucepan and stir mixture constantly with wooden spoon until mixture develops thin, sauce-like consistency. Temperature of mixture should read 170° Fahrenheit when checked with instant read thermometer.
When desired consistency and temperature are achieved, carefully pour lime curd through fine mesh sieve and into glass measuring cup. Discard any sediment left in sieve.
Immediately pour strained lime curd on top of warm, lightly golden crust in baking pan, covering crust completely and evenly. Spread lime curd into corners of baking pan as needed.
Return baking pan to preheated oven. Bake lime bars 10 minutes, then begin checking doneness. Continue baking as needed, checking doneness every 1 to 2 minutes, until lime filling is opaque, shiny, and jiggles slightly in center of pan.
When lime filling is ready, carefully remove baking pan from oven and place on wire cooling rack. Cool lime bars 45 minutes or until room temperature, then place baking pan in refrigerator. Refrigerate until completely chilled.