Step 1

Preheat the oven to 350°F. Lightly grease 6 ramekins with butter and line the bottoms with parchment paper. Set aide.

Step 2

In a large bowl, whisk together the egg yolks, evaporated milk, condensed milk, and vanilla extract. Set aside.

Step 3

In a heavy bottom pot over medium heat, whisk together the light brown sugar and water and cook until the sugar has dissolved. Then lower the heat and continue whisking until the mixture has thickened slightly and is a golden brown.

Step 4

Use a spoon to divide even amounts of the melted brown sugar between 6 ramekins. Gently tilt ramekins from side to side to coat the entire bottom with melted sugar. Allow the sugar to set and slightly harden, which takes just a couple of minutes.

Step 5

Pour the egg yolk milk mixture through a sieve evenly into each ramekin.

Step 6

Place the ramekins onto a rimmed baking sheet, then pour in boiling water into the baking sheet just about 3/4" to 1" deep.

Step 7

Carefully place the baking sheet into the middle oven rack and bake at 350°F for 50 to 60 minutes, just until the custard centers are set and no longer very jiggly. Remove from the oven and allow to cool at room temperature, then refrigerate for at least 30 minutes, just until the leche flans are chilled, or up to overnight.

Step 8

Serve in ramekins. Or, run a thin butter knife along the side edges or each ramekin to loosen the edges and then carefully flip ramekins over plates and serve on plates.