Have half cup butter at room temperature. Sift together flour, baking powder, and one third cup sugar. Cut the half cup butter into dry ingredients with a pastry blender until mixture resembles cornmeal. Beat one egg and stir into flour mixture. Pat into a 23 cm flan pan, pushing about one third of the dough up against sides of pan. Chill half hour. Soften remaining half cup of butter and beat remaining sugar into it. Beat in two eggs, one at a time, beating well between each. Stir in almonds and extract. Pour over pastry. Bake at 180ºC or 30 minutes. Remove from oven and cool one hour. Spread jam over torte. Mix powdered sugar with enough lemon juice to form a spreadable icing. Use a pastry bag fitted with small hole to pipe icing in a design over top of torte.