Preheat oven to 350 degrees F (175 degrees C). Grease and flour an 8x12 inch pan. Sift together the flour, baking powder, 1 teaspoon mixed spice and 1/2 teaspoon nutmeg. Set aside.
1¼ Cups all-purpose flour, 2 tsp baking powder, 1 tsp mixed spice, 1/2 tsp ground nutmeg
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Beat in the flour mixture alternately with the milk. Spread batter into prepared pan. Sprinkle the chopped rhubarb over the batter.
½ Cup butter, 1 Cup white sugar, 2 eggs, 1 tsp vanilla, 1/2 Cup milk, 6 rhubarb stalks, chopped
In a small bowl, mix together the brown sugar, 1/2 teaspoon mixed spice, 1/4 teaspoon nutmeg and slivered almonds. Sprinkle over top.
¼ Cup brown sugar, 3/4 Cup slivered almonds, 1/4 tsp ground nutmeg
Bake in the preheated oven for 50 to 60 minutes, or until the cake springs back when lightly tapped. Serve warm or cold.