In a food processor, combine flour, sugar, cold butter, eggs, baking powder, and salt. Pulse until it transforms into a crumb-like texture.

Wrap the crumble mixture in plastic wrap and place it in the refrigerator while you prepare the plum filling.

Dice the plums into small pieces. In a mixing bowl, combine these plums with lemon juice, flour, and sugar until they are well coated.

Spread half of the chilled crumble mixture evenly over a large baking sheet, approximately 13x18 inches. Then layer the plum filling atop this base.

Crumble the remaining dough over the top to fully cover the layer of fruit.

Bake in a preheated oven at 350°F for around 40 minutes, or until the top achieves a beautiful golden brown hue. Allow it to cool before serving. It pairs wonderfully with vanilla ice cream!