This trifle is no trifling matter. It's as delicious as it looks.
2 cups milk
2/3 cup granulated sugar
2 tbsp cornstarch
2 tbsp all-purpose flour
1 tsp vanilla
6 cups frozen loose-pack unsweetened raspberries
1/4 cup granulated sugar
1 cup 35% cream
2 300-g pound cakes, or plain yellow cakes, store-bought or homemade
First, make the custard filling. In a blender, combine the milk, eggs, sugar, cornstarch and flour. Blend until smooth, then pour into a medium-sized heavy saucepan. Cook, stirring almost constantly with a whisk, over medium-low heat until the mixture becomes thick and smooth - 5 to 8 minutes. Don't leave the room for a minute - the custard will thicken all of a sudden. Remove from heat and stir in the vanilla, whisking until smooth. Cover the surface of the hot custard with a layer of plastic wrap (to prevent a skin from forming), and refrigerate for an hour or two until completely cool.
Toss the frozen raspberries with ¼ cup (50 mL) of sugar and let them thaw, mashing them slightly (not completely, kids) to make a goopy mixture. Set aside.
Cut the cake into slices ½ in. (1 cm) thick. Set these aside, too.
Beat the whipping cream with an electric mixer until stiff. Fold half of the whipped cream into the cooled custard and set aside the other half. OK, now you're ready to assemble your masterpiece.
Find a pretty glass bowl (you want to be able to see the layers, don't you?) about 10 in. (25 cm) in diameter, with a capacity of 3 quarts (3 L). Have your child help you arrange cake slices in the bottom, cutting them to fit snugly together to make a solid layer of cake. Over this spread half of the raspberry glop. Cover the raspberries with half of the custard mixture. Repeat: cake layer, the rest of the raspberries and the rest of the custard, smoothing the top nicely to hide the raspberries. (You may not use all the cake slices. Eat any leftovers to destroy the evidence.) Decorate the top of the trifle (gorgeously) with dollops of whipped cream and additional raspberries (if you have them). If not, sprinkles will do.
Cover the bowl tightly with plastic wrap and refrigerate for 4 hours (or overnight) before serving.