My grandmother's lemon meringue pie was a traditional Christmas and mid-winter dessert. As a child I loved it. Lemon meringue pies are a very traditional North American pie. There are also other related pies such as key lime pie.
They have a history going back to the early days when Canada and America were mostly wilderness and were poor undeveloped countries. Before these pies were made with lemon juice they were made with vinegar, often apple vinegar. In the middle of winter, a pie could be made that tasted a bit like apples, when there were no fresh apples available. Vinegar pies were sometimes called desperation pies. Poor people made desperation pies. People had to use their wits (natural intelligence) and hard work to make good things to eat when not much food was available.
The vinegar pie was pioneer food. The first European settlers in wild places were called pioneers. Vinegar pies were made from things that any successful pioneer would have in the middle of winter. To make a vinegar pie all one needed was water, chickens, vinegar, sugar, wheat and salt. The water came from a well or a river. The chickens gave you eggs. The wheat was ground into flour. From these ingredients a delicious winter pie could be made. It was hard work to make a pie in early America, but children remembered it all their lives.
Eventually people in North America became more prosperous. They got access to more food ingredients and lived more comfortably. Some pioneers settled in warm places, such as California. People started growing lemons in these warm places. Lemon juice replaced vinegar. A fancy whipped egg-white topping, called a meringue was added when people had the time to put in the extra effort. From this pioneer history, North American family cooking traditions were slowly created.