1. Grate 2 teaspoons peel from lemons. With a zester or Asian shredder, make a few long, slender strands of peel from Meyer or regular lemons; set aside. Ream 1 1/3 cups juice from the lemons.
2. In the top of a double boiler, mix cornstarch and sugar. Stir in juice and grated peel. Fill bottom of double boiler with 1 inch water. Place pans over high heat and bring water to a simmer; adjust heat to maintain simmer. Stir until mixture is thick and shiny, 8 to 9 minutes. In a bowl, whisk eggs to blend. Whisk in about 1/2 cup lemon mixture, then return all to pan. Stir until mixture is very thick and reaches 160° on an instant-read thermometer, about 5 minutes.
3. Remove top pan. Place in a bowl of ice and stir often until mixture is cool to touch, about 6 minutes.
4. In a bowl, beat cream with a mixer until stiff. Fold in lemon mixture, then spread evenly in pastry shell. Scatter reserved strands of peel on top. Chill, uncovered, until slightly firm to touch, about 2 hours. Serve, or wrap airtight and chill up to 1 day.