For shards, line a large baking tray with baking paper. Melt 200g chocolate in a bowl over a saucepan of simmering water (don't let bowl touch water).
Thinly spread chocolate onto tray with a palette knife. Cool, then chill until set.
For pastry, place flour, spread and icing sugar in a food processor and whiz to combine. Add 2-3 tablespoons iced water and process until a smooth ball.
Wrap in plastic wrap. Chill 20 minutes.
Preheat oven to 180°C.
Roll out pastry and use to line a 23cm loose-bottomed tart pan. Chill for 10 minutes. Line pastry with baking paper and pastry weights or raw rice and blind bake for 15 minutes. Remove paper and weights or rice, then cook for 5 minutes.
Reduce oven to 160°C. Place soy milk and remaining chocolate in a saucepan over low heat, stirring, until melted. Beat the eggs, cocoa, cornflour and sugar in a bowl, whisk in the chocolate mixture and add almond meal. Pour into pastry case, bake for 30 minutes until just set, then cool. Sprinkle tart with caster sugar. Cut chocolate into shards and garnish tart.
