Combine plums, granulated sugar, lemon juice, and cinnamon in the loaf pan.
In a medium bowl, combine flour with brown sugar, walnuts, and salt.
Use a pastry cutter to cut in the butter to a coarse-crumb texture. Spoon over plum mixture. Bake for approximately 30 minutes until the top is golden brown and plums are bubbly.
Serve warm topped with French vanilla or vanilla bean ice cream lightly dusted with ground ginger.