Place a saucepan with water and bring it to a simmer over the stove. You can also use a double boiler if you own one.
Place beaten eggs in a glass bowl, or double boiler bowl and slowly whisk in the sugar. Slowly add the lemon juice and the cubed butter.
Place bowl over saucepan.
Whisk constantly to combine all the ingredients well as the butter melts over the saucepan.
Continue to stir until the mixture begins to thicken.
When mixture is thick, remove from heat and allow chill in the refrigerator.
Whip 1 cup of heavy cream with 1 Tbsp. confectioner's sugar until you have stiff peaks.
Place lemon curd in a piping bag and pipe onto tartlets. Place the whipped cream in a piping bag and pipe over the curd.
Keep in refrigerator until ready to serve.