Wellington beef is not a New Zealand dish, but just happens to have the same name as Wellington, the capital of New Zealand.
According to legend, this Wellington steak was named to commemorate the first generation of Wellington generals-Arthur Wellesley defeated Napoleon at the Battle of Waterloo. In fact, the history of this dish is quite controversial. Both France and Britain believe that this dish was invented by themselves, and the debate has never stopped.
But it is generally believed that in 1450, the French invented "meat pie", which was baked in the oven with minced meat wrapped in dough. This "meat pie" can be regarded as the predecessor of Wellington steak, and Wellington steak is improved on this basis. Mushrooms, beef, truffles and wine are mixed together and put into the pie crust to bake food.
Small science:
In fact, it's not just steak, but the practice of wrapping staple food with pasta is called Wellington, salmon is called Wellington Salmon, chicken is called Wellington Chicken Chop, and mushroom dish is called Wellington Mushroom dish.