Preheat waffle iron.
Melt butter in a skillet over medium heat. Add plums and ginger; season with allspice and sauté to tender, 5 minutes. Add maple syrup and reduce heat to low.
Heat a drizzle of oil in a large skillet over medium-high heat. Add ham steak and cook to brown on both sides, 8-10 minutes, turning occasionally. Quarter steak into 4 portions.
Combine waffle mix according to package directions for 4 individual portions. Stir in nuts and nutmeg. Brush waffle iron with melted butter and cook waffles to deep golden brown.
Top waffles with ham steak and lots of maple plums, and serve.