1. Make a simple graham cracker pie crust using a recipe from the back of the graham cracker package (or buy a prepared crust).
2. Zest the key limes and put zest in a small mixing bowl. Juice the limes (6 tbsp. of juice). Add 2 tbsp. of the juice to the zest. Then add 4 oz. cream cheese, 1 tsp. rosewater, and 1/2 cup sugar.
3. Place a small saucepan on the stove, and put reserved 4 tbsp. of lime juice in it. Retreive mixing bowl from freezer and whip 1/2 cups heavycream until just before in forms soft peaks. Sprinkle on 2 tbsp. sugar and give one more whack with mixer.
4. Add heavy cream mix to bowl with zest and whip until smooth.
5. Heat lime juice on stove, not quite to a boil, and sprinkle on 1/2 tsp. agar agar powder. Remove from heat immediately and whisk rapidly until powder is dissolved.
6. Pour lime and agar mixture into cream cheese mix, and fold quickly with spatula. Pour that combination into the whipping cream and mix on high. It should congeal instantly into stiff peaks. Place completed mixture into crust and refrigerate for an hour or so.

*This recipe also works very well with lemon, resulting in a lemon chiffon pie. You might like to add 1/2 tsp. cardamom to the lemon version.