1 c. sugar
1 c. lime juice
Zest of 3 limes
1 stick unsalted butter, melted
1 Tbsp. cornstarch
1 Tbsp. water
Whisk together sugar and eggs until smooth. Stir in lime juice, butter and lime zest.
In a separate bowl, stir cornstarch into the water until it is completely dissolved. Return to the lime mixture and cook over medium heat on stove top for 5 minutes, whisking constantly. Whisk cornstarch mixture into lime mixture and continue to cook for another 2 to 3 minutes or until thick and bubbly.
Remove from heat and continue to stir for another minute or two. Let rest and finish cooling for about 10 minutes. Filling is best when it has been refrigerated for a few hours. Once curd is cool you can place filling into decorating bag.