For ham croissants, roast onion in pan until translucent, add ham and fry everything until golden. Meanwhile, put the sour cream in a bowl, add the roasted onion and ham and season with salt and pepper.
If it is too liquid, add a small amount of flour. Preheat the oven to 200 degrees and line 2 baking sheets with baking paper. Divide the canned croissants from the refrigerator into 6 croissants, cover with the ham and sour cream filling and roll up.
Brush everything with a beaten egg and put the ham croissants in the oven for about 20 minutes at 180 degrees hot air.