For the early cabbage strudel, first prepare the strudel filling. For the strudel filling, quarter the spring cabbage, cut out the stems and cut crosswise into strips.
Halve the leek lengthwise and cut crosswise into strips. Peel the carrot, quarter it lengthwise and cut it into slices. Peel and dice the onion, peel and finely chop the garlic.
For the tomato sauce, peel the tomatoes and the bell pepper, remove the seeds and cut into cubes. Peel and dice the onion, peel and finely chop the garlic.
Heat some olive oil in a pot, brown the minced meat and remove it from the pot. Add a little olive oil to the drippings and sauté the onion cubes until translucent.
Add the leek strips, the garlic and the carrot slices, let everything brown and add the early cabbage strips. After the cabbage has collapsed, season it, add some beef broth and let it soften in the open pot on low heat.
It is important that practically no liquid remains. After the cabbage has cooled down, mix in the minced meat.
Then lay the strudel sheets on a kitchen towel and brush each one with melted butter. Spread the filling on about a third of the strudel sheets, crumble the feta cheese and spread it on the filling.
After folding in the side edges, roll up the strudel, brush it with more melted butter and place it in the preheated oven.