• Cover a lint-free dish towel with powdered sugar and shake off the excess sugar. This is what we'll use to shape and roll the cake. The powdered sugar prevents the cake sticking to the towel.
• Preheat the oven to 350 °F. Line a jelly roll pan or a 13x19-inch baking dish with parchment paper. Give the parchment a light spritz of nonstick spray.
• Beat the eggs with an electric beater until the eggs are foamy and pale yellow.
• Gradually beat in the sugar
• Beat in ⅓ cup of water and 1 teaspoon vanilla extract
• Sift together the flour, baking powder and salt
• Gradually beat the flour mixture into the cake batter until fully incorporated - be gentle; we want to avoid deflating the whipped-up eggs!
• Pour the cake batter into the prepared baking dish or jelly roll pan.
• Bake at 350 °F for about 15 minutes. The cake might not be very brown on top, but a toothpick inserted into the center of the cake should come out clean.

Shape the cake:

• As soon as the cake is cool enough to touch, pick up the edges of the parchment paper and pull the cake out of the pan. Gently the cake face-down on the sugar-covered dish towel.
• Gently peel the parchment paper off the cake.
• While the cake is still warm, roll the dish towel up tightly with the cake inside. This will prevent cracking and tearing when you roll the cake later.
• Gently unroll the dish towel and the cake, and allow the cake to sit and cool for at least 30 minutes.
• Make the raspberry jam:
• The jam can be made up to 3 days ahead of time and stored in an airtight container in the fridge. Or, you can make the jam while you're waiting for the cake to cool.
• Combine the raspberries, sugar and water in a saucepan over medium-high heat. Cover the saucepan and bring to a boil.
• Turn the heat down to medium-low and simmer for about 15 minutes with the lid on.
• Remove the lid and simmer for another 15 minutes, until most of the liquid evaporates and the raspberries reach a jam-like consistency.
• Remove from the heat and stir in the vanilla extract

Assemble the jelly roll:

• Spread the raspberry jam evenly over the top of the sponge cake.
• Roll up the sponge cake.
• Wrap the dish towel tightly around the outside of the cake roll. The towel will hold the cake securely in a rolled-up shape. Leave the cake tightly rolled inside the dish towel until serving time.
• Just before serving, top with whipped cream (or I used Cool Whip), raspberries and more powdered sugar.