Preheat oven to 375°F. Butter an 8 x 8 baking pan and set aside.
In a medium bowl, cream butter and sugar together. Add eggs one at a time, then almond extract and mix on medium for a couple minutes.
In a small bowl, combine flour, baking powder, almond meal, salt, nutmeg, cinnamon and zest. Add the dry mixture to the wet mixture and mix into a batter. Pour into the prepared pan and arrange plum slices on top of the batter in a decorative fashion. Sprinkle with lemon juice and dust with the sugar.
Bake 30-35 minutes or until sides begin to pull away and cake is golden brown. Cool and serve. It is also delicious with whipped cream or ice cream.