Cut the mangoes and the washed strawberries into cubes of approx. 1.5 x 1.5 cm. Bring the fruits to a simmer in a saucepan with lemon juice and water. Cook until the fruit is soft. Then puree everything finely with a hand blender. Add the preserving sugar and vanilla sugar and bring to the boil according to the instructions on the package.
Pour the jam into washed and boiled jars with twist-off closures and then turn upside down for five minutes.