To make the lemon curd: Grate 1 tablespoon lemon zest. Cut the lemons in half and squeeze 1/2 cup juice.

Beat the butter and 1 cup of sugar at medium speed with an electric mixer until blended. Add eggs 1 at a time, beating just until blended after each addition. Gradually add lemon juice to mixture, beating at low speed just until blended. Stir in zest. The mixture will look curdled.

Transfer to a heavy, 4-quart saucepan, cook on stove top, whisking constantly over medium-low until mixture thickens and coats back of a spoon, 14-16 minutes.

Place a sheet of plastic wrap directly on the warm lemon curd. Chill 4 hours or until firm.

To make the whipped cream: Beat the heavy cream at medium speed with an electric mixer until soft peaks begin to form. Gradually blend in the remaining 1 tablespoon sugar and the vanilla. Beat until stiff peaks form. Cover and refrigerate.

To build the parfaits: In 4 wine or dessert glasses, add a layer of raspberries then a layer of lemon curd and a layer of whipped cream. Continue this layering pattern until glasses are full. Finish with a fresh raspberry layer.

Serve immediately or refrigerate up to 4 hours before serving.