Step 1

Preheat your oven to 350°F/180°C.

Step 2

Grease a 15-inch x 10-inch Swiss roll pan with baking spray or brush it with melted butter.

Step 3

Line the pan with parchment paper.

Step 4

In a mixing bowl, whisk the eggs for 3-4 minutes until they become frothy.

Step 5

Gradually add the sugar, whisking after each addition. Continue whisking for another 5 minutes until pale and thick and the whisk leaves trails in the mixture.

Step 6

Combine the vegetable oil, sour cream, and vanilla extract together in a jug, then mix into the egg mixture.

Step 7

In a separate bowl, sift the flour and baking powder, then whisk in the salt.

Step 8

Fold one spoonful of the flour mixture at a time into the egg mixture using a balloon whisk to avoid lumps. Repeat until all ingredients are fully combined.

Step 9

Pour the batter into the lined pan, ensuring to scrape out the bowl with a spatula.

Step 10

Spread the batter evenly using an offset spatula or cake scraper.

Step 11

Tap the pan on the work surface several times to release any air bubbles.

Step 12

Bake the sponge for 14-16 minutes or until the center springs back lightly when pressed.

Step 13

While the sponge is baking, lay a 20-inch length of parchment paper over a tea towel on a cutting board and sprinkle the reserved sugar onto the paper.

Step 14

Turn the baked sponge out onto the parchment paper. Carefully remove the lining parchment paper and cut each short end on the diagonal to neaten and aid rolling.

Step 15

Roll the sponge up inside the parchment and wrap it in the tea towel to cool completely.

Step 16

Sift the skim milk powder and powdered sugar into a medium bowl containing the cream and vanilla extract.

Step 17

Beat with a hand mixer until firm peaks begin to form. Using a hand mixer helps to prevent over beating.

Step 18

Carefully unroll the cooled sponge and spread a generous layer of jam over it. Repeat with the cream.

Step 19

Re-roll the cake and chill for 2 hours before serving.

Step 20

trim the ends and transfer the Swiss roll to a serving dish. Dust with powdered sugar and serve with fresh strawberries.