Preheat the oven to 425 degrees F. Grease and flour a 10-inch springform pan. In a large bowl beat the butter and brown sugar until very creamy. Stir in the egg and lemon peel. Sift together the flour and baking powder and add a few tablespoons to the sugar and egg mixture. Then add the remaining flour. With your fingers quickly work the mixture into crumbs. Place half the crumbs in the prepared pan and spread them with the jam.
Combine the remaining crumb mixture with the ground almonds and sprinkle it over the jam. Bake 50 to 60 minutes or until brown. Remove the cake from the pan and cool it on a wire baking rack.
Sift confectioners’ sugar over the cooled cake.