Fireworks Raspberry Tart

I made this for the Festival of Lights fireworks on English Bay. It was a resounding hit. A bit of a challenge to carry since it is a bit delicate - I baked it in a spring form pan with the edges cut half-way down the pan's lip, and that seemed to work fine. This is made with pastry cream - the difference between pastry cream and custard is that the former uses flour to thicken. 

1 cup milk

2 tsp vanilla extract

3 egg yolks

¼ cup sugar

2 Tbsps. flour

¼ cup heavy cream

1 lb fresh raspberries

1 9"/23 cm cookie crust, baked

1. Put the milk in a saucepan. Split the vanilla bean, scraping the seeds into the milk, then drop in the pot. Heat to a simmer, remove from heat, cover, and set to infuse 10 minutes. (If using extract, just bring milk and vanilla just to a boil and set aside to cool.)
2. Beat the yolks with the sugar until pale. Beat in the flour. Pull the vanilla bean from the milk and whisk the milk gradually into the egg mixture. Pour back into the saucepan, bring to a boil, and cook one minute. Remove from the heat (optional: stir in 1 tablespoon framboise liqueur). Strain into a bowl, cover with plastic wrap, and set aside to cool. 
3. When chilled, stream the cream in and mix with whisk until smooth.
4. Spread the pastry cream evenly in the base of the tart. Arrange the berries neatly over top.