For me the tastiest vegetables are tomatoes. Preferably fully ripened, which really taste like summer. Unfortunately, especially in the colder months there are often tomatoes on offer that are not yet fully developed.
Many people know that apples should not be stored together with other fruit because they release ethylene gas, which is a natural ripening agent. But you can use this effect wonderfully for the not yet mature tomatoes: You put five or six tomatoes in a paper bag (maybe you can also use plastic - I have not tried it yet) and add an apple. After a short time, the tomatoes are ripened and taste much better.