Pour soy milk into a medium-sized saucepan. Add salt, sugar, and vanilla sugar. Heat over medium heat; do not stir!

Meanwhile, in a separate bowl, combine whipped topping, egg yolks, and cornstarch. When the milk comes to a boil, remove ¼ cup of heated milk, and quickly whisk it into the egg mixture to temper the eggs. Pour the mixture back into the saucepan and stir constantly. Cook for one minute, until custard thickens.

Remove from heat and stir in margarine and vanilla extract. Transfer to a medium-sized bowl, and cover with plastic wrap to prevent a skin from forming. Place in refrigerator until cake is ready.

Preheat the oven to 350°F. In a mixer bowl, beat egg whites until stiff. Add in ½ cup sugar and beat. Add yolks individually, beating after each addition. Add ¼ cup sugar and lemon juice. Beat until light and fluffy. At low speed, gradually add flour and baking powder.

Line a cookie sheet with Gefen Parchment Paper. Spread the batter onto the sheet and bake for 12 minutes. Remove from oven, and turn onto a clean towel that is dusted with powdered sugar. Roll the short side up immediately. Allow to cool completely.

In a small bowl, combine chocolate glaze ingredients and whisk until smooth. Drizzle over the top of the roll.

Refrigerate until serving.

When the cake is cool, gently unroll it. Spread cooled custard filling on it and gently roll back up. Place the cake seam-side down on a serving tray.