With the rack in the middle position, preheat the oven to 180 °C (350 °F). Line a 20-cm (8-inch) square pan with parchment paper, letting the paper hang over two sides. Butter the other two sides.
In a bowl, combine the flour and salt. Set aside.
In another bowl, cream the butter and sugar with an electric mixer. Add the ground almonds and amaretto and stir to blend. Add the eggs, one at a time, beating until smooth. On low speed, add the dry ingredients. Spoon the batter into the prepared pan. Bake for about 30 minutes or until a toothpick inserted in the centre of the cake comes out clean. Let cool. Unmould onto a wire rack and let cool completely.
On a work surface dusted with icing sugar, roll the almond paste into a square about 1-cm (1/2-inch) larger than the cake. With a brush, remove any excess sugar. Cover the top of the cooled cake with the almond paste.
With a sharp knife, cut around the cake to even out the almond paste. Cut the cake into 16 squares.
Place on a wire rack over a baking sheet.
Lilac Icing Glaze
In a bowl, combine all the ingredients with an electric mixer until smooth. Add water, if needed. The mixture should be runny, but thick enough to leave an opaque layer on the cake. Correct the color by adding food coloring, as needed.
With your fingers, hold a cake on its top and bottom sides. With a spoon, drizzle the glaze on the sides of each cake to coat. Place the cakes on the rack and cover the top of the cakes with glaze. Place a few crystallized lilac flowers or dried sprigs of lavender on the petits fours. Let stand for about 30 minutes.
This Almond Pound Cake is an Italian preparation consisting of almonds, sugar, butter and eggs with a little flour or cornstarch. It is a very moist cake that keeps for several days.