Pour the milk into a small, heavy-bottomed saucepan. Split the half vanilla pod lengthwise, scrape out the seeds, and add the seeds and pod to the milk. Over medium heat, bring the milk just to a boil, stirring occasionally.

Nest a metal bowl in a slightly larger bowl filled with enough ice water to come halfway up the side of the smaller bowl. Set aside.

In another small bowl, whisk together the egg yolks, sugar, and cornstarch. Whisk in 1⁄4 cup of the hot milk to temper the egg yolks, then quickly whisk the egg yolk mixture into the saucepan of hot milk. Heat the mixture over low heat, stirring constantly with a wooden spoon or heatproof spatula. Make figure eights as you stir so no custard sticks anywhere in the pot.

Cook until a clean line remains when you dip the spoon in the custard and run your finger through it or an instant-read thermometer registers 175°F, 6 to 10 minutes.

Quickly strain the custard into the bowl over the ice water bath, discard the solids, and stir until cool. Cover the surface of the custard with plastic wrap to prevent a skin from forming and refrigerate until chilled.

In a small bowl, toss together the strawberries, jam, lemon juice, and honey. Let macerate for 10 to 15 minutes. Gently fold in the 2 cups of raspberries and let sit for 5 minutes. Place a layer of berries on the bottom of 6 glasses.

Place 2 rounded tablespoons of custard in each glass, followed by 2 heaping tablespoons of the whipped cream. Repeat these three layers one more time, then top each parfait with three raspberries. Chill for at least 30 minutes before serving.