Separate the eggs into whites and yolks. Beat the yolks with a mixer with 50 g of sugar and a pinch of salt until increased in volume and pale.
In a separate bowl, beat the whites, adding 70 g of sugar in three additions. Pour the yolk mixture into the whites and fold together quickly but gently.
Sift in the flour with the baking powder, gently fold with a spatula, then at the end pour in the milk with the vegetable oil and mix - the batter is ready.
Pour the batter onto a parchment-lined baking sheet and bake for 30 minutes in an oven preheated to 170 C.
Flip the finished sponge onto another sheet of parchment right away, peel off the old one, and let it cool; you can trim the edges.
For the frosting, beat the strained sour cream with the condensed milk, spread it over the entire sheet, place the strawberry slices, and gently roll it up.
Refrigerate the roll for a couple of hours, then slice. Enjoy!