Vanilla Lemon Mille-Feuille: A Citrus-Kissed French Classic

2 cups whole milk

1/2 cup granulated sugar

4 large egg yolks

1/4 cup cornstarch

2 tbsp unsalted butter

1 tsp vanilla extract

Zest of 1 lemon

2 tbsp fresh lemon juice

For the Glaze (optional):

1/2 cup powdered sugar

1–2 tsp lemon juice or milk

Instructions
1. Prepare the Puff Pastry