- Preheat oven to 350°F. Grease two 8-inch round cake pans and the bottoms with parchment paper.
- Cream the butter and sugar together in a mixing bowl until the mixture is pale in color and light and fluffy. Add the eggs one at a time, beating well after each one.
- Sift the flour and salt and carefully add to the mixture, folding it in a with spatula. Divide the mixture between the pans and smooth the tops of the batter.
- Place them on the same shelf in the center of the preheated oven and bake for 25-30 minutes, until well risen, golden brown, and beginning to shrink from the sides of the pans.
- Remove from the oven and let it stand in their pans for 1 minute. Loosen the cakes from around the edge of the pans using a small knife. Turn the cakes out onto a clean dish towel, remove the parchment paper, and invert them onto a wire rack.
- When completely cool, sandwich together with jam and sprinkle with the powdered sugar. The cake is best when freshly baked but will keep well, stored in an airtight container for up to 1 week.