Add the warm milk and the vanilla and whisk well. Heat over medium heat, whisking constantly until the mixture thickens. When you notice it is almost ready to bubble, remove from heat and transfer to a clean, heatproof bowl. Add the butter and mix well.
Make the walnut cake: Transfer the eggs, the white sugar, the brown sugar, the vanilla, and the salt to the bowl of your electric mixer and beat until pale and fluffy. When done, the mixture should resemble thick shaving foam.
In another bowl mix the flour with the cinnamon and the baking powder and sift them to aerate them. Add the flour mixture to the egg mixture gradually, folding with a spatula. Don’t over mix because the mixture will deflate. Add the walnuts and fold just until evenly incorporated.
Pour the batter into the baking pan and bake for 30-35 minutes or until a toothpick inserted in the center comes out clean. Let it in the pan to cool.
Cover the walnut cake with the custard and store the cake in the refrigerator until ready to serve. Just before serving, sprinkle the cake with a mixture of toasted chopped walnuts, toasted sesame seeds and a pinch of cinnamon and drizzle some thyme honey.
Prep time don't include cooling times.
You can increase or decrease the amounts of the water and sugar for the syrup by 1/4 of a cup depending on how sweet you want the cake to be.