Start by adding the diced strawberries, the sugar and the lemon juice into a saucepan, mix very well, bring to medium-low heat and let it cook for 5 minutes, always stirring.
The right cooking point is that in which strawberries have not broken down and a syrup was formed.
Transfer the strawberries to a bowl and set aside.
In a bowl, place the eggs and the sugar, mix well until combined. Add the oil and the milk, mix for another 2 minutes and set aside.
Into another bowl, put the wheat flour, the baking powder and the vanilla essence, mix for 1 minute.
Now transfer all this flour mixture to the bowl with the beaten eggs, mix well until combined.
Transfer all this batter to a small rectangular baking mold greased with butter and flour.
Finally, pour the strawberry sauce into the center of this batter, making a straight line with it.
Bake in a preheated oven at 180°C (356°F) for 30 to 40 minutes.
Note: Baking time may vary depending on the power of your oven.
Sprinkle some icing sugar on top and serve.