How lovely! I've gotten pretty good at growing vegetables, but flowers, not so much.
Poland has a variety of hardiness zones, which will determine how much longer you have in your growing season. I would suggest things like brassicas (which include kale and broccoli), as they can handle temperatures a bit below freezing. But keep in mind the size of your balcony, as they can get pretty big.
If you can buy seedlings of annual herbs like parsley, dill, basil, there's still time for a good harvest even in the colder areas of Poland. Do you have space where you can bring some pots inside?
[Vegan] and [Vegetarian] are quick ones that come to mind. Maybe also like the region of the cuisine? i.e. [Chinese], [Peruvian], or maybe the type of meal [Breakfast], [Appetizer].
Ooooh them's fighting words. Have you tried a burger with a homegrown tomato? Pretty night and day, might just change your mind.
[Image description: a plate with a burger and sides. The burger is open and ready to be assembled, one bun has sauce and a slice of an heirloom tomato, the other has the patty, cheese, pickles and bacon.]
Desperately try to foist them on friends, family, coworkers, neighbors, passing dog walkers, the mailman... anybody who'd take some 😆
Beyond that, we'd eat tomato based meals for breakfast, lunch and dinner, and we canned dozens of pints of salsa and sauce (that we're still eating!).
It's definitely a learning curve to start your plants from seed, but seeds can be gotten cheap and are easy to transport. I find beans/peas to be pretty easy to grow from seed, and their vertical growth means they don't take up too much space.