In a small heavy saucepan stir together egg yolks, milk and sugar. Cook and stir over medium heat until mixture is thickened and coats the back of a metal spoon. (Do not boil.)
Remove pan from heat. Quickly cool mixture by placing saucepan in a large bowl of ice water for 1 to 2 minutes, stirring frequently.
Stir in vanilla. Pour mixture into a small bowl. Cover surface with plastic wrap to prevent a skin from forming. Chill for at least 2 hours or up to 24 hours before serving. Do not stir. (Custard will be thickened but will not be set.)
In a small bowl, combine graham cracker crumbs, almonds, and ground cinnamon.
Divide half of the graham cracker mixture among 6 tall 8 ounce glasses, small parfait glasses, or small dessert dishes. Layer with half of the raspberries and /or strawberries and half of the chilled custard. Top with half of the blueberries. Repeat layers.