Pour the milk into a small pot and place over medium heat until small bubbles form around the edges.

In a medium mixing bowl, whisk the egg yolks with the maple syrup, cornstarch, and salt.

Slowly pour the hot milk over the egg mixture, while whisking, to warm the eggs.

Place the mixture back into the pot and place over low heat. Cook, stirring constantly, until the mixture comes to a bubble and becomes very thick.

Stir in the vanilla and transfer to a heat safe container. Lay plastic wrap over the surface. Chill for 2 hours.

Place the flour, sugars, baking powder, salt, and spices in a large mixing bowl and whisk to combine.

Add the soft butter, and mix on low speed until the mixture resembles wet sand.

Stir in the eggs, one at a time, scraping the bottom and sides of the bowl with a silicone spatula after each addition.

Add the pumpkin, Greek yogurt, and vanilla, and mix on medium-low speed for about 90 seconds, to aerate the batter and develop the cake's structure.

Bake for 40-45 minutes, or until a tester inserted in the middle of the cake comes out clean or with a few moist crumbs. Cool completely and fill with pastry cream.

Preheat the oven to 265 degrees F.

Break up the white chocolate into pieces, and scatter in the bottom of a baking dish (I used a 9x13 glass dish).

Bake in the oven for 40 minutes, stirring every 5 minutes. Chocolate will become thick and chalky.

After 40 minutes, remove from the oven and transfer to a bowl. Stir until the chocolate becomes liquefied.

Heat the cream until small bubbles form around the edges. Pour the hot cream over the caramelized white chocolate. Whisk to combine.

Allow to cool slightly, then pour over the cake, using a metal spatula to spread in an even layer.