Beat egg whites until soft peaks form. Gradually beat in sugar and continue beating until thick and glossy and stiff peaks form. Gradually fold in ground almonds and confectioners sugar.
Draw 3 (9 inch /23 –25 cm) circles in parchment paper. Butter and flour circles. With a metal spatula fill in two circles with meringue. Fill pastry bag with meringue and pipe in third circle forming a lattice top.
Bake meringue in 200 °F (100 °C) oven for 2 hours. Remove from oven, cool on rack and peel off paper.
Place sugar and milk in a medium heavy bottom pan. Bring to a boil and continue cooking, stirring constantly, until mixture thickens and bottom of the pan can be seen. Fold in almonds. Cool.
To assemble, cover one meringue with milk mixture and spread a thin layer of chantilly cream. Place another meringue on top and repeat. Top with lattice meringue.
Decorate with almonds and chantilly cream.