I used Splenda instead of sugar. Melted butter separately before I added it. Added 1 tsp lemon extract. Got impatient at about 7 minutes and added 1 tsp cornstarch dissolved in 2 tbsp cold water. That thickened it right up. Put into a clean bowl and placed into an icewater bath to cool. Sort of curdy looking but the taste is ab FAB! Sweet and tart, amazing! Plan to use on sugarless lemon cheesecake (Suzanne Somers recipe.)