Generously grease an 8x8-inch square baking pan and set aside.

In a large pot over medium heat, mix 1 cup coconut milk and 1 cup water. Add the glutinous rice and pandan leaves. Bring to a simmer then turn heat to low and cover. Let it cook until all liquids are absorbed. The rice should only be almost cooked at this point, not fully cook or the biko will be mushy. They should be softer but has not fully expanded and it is ok to see some grains are still "chalky" at the center. If it is too undercooked, you can add a bit more water (start with ¼ cup) pour along the edges.

While waiting, prepare the latik syrup by combining the 2 cups coconut milk and 1 cup dark brown sugar in a large pan. You can add the vanilla extract if desired. (I do). Cook over medium heat while constantly stirring. Cook it until the liquid is reduced into a thick syrup, the color should also have darkened into deep brown caramel. Reduce the heat to very low at this point.

Scoop and reserve ½ cup of the latik syrup for the topping later. Add the cooked rice (without the pandan leaves) to the pan with the remaining latik syrup. Gently fold the sticky rice and the syrup until completely coated. Cook while stirring occasionally, until the rice completely absorbs the syrup, but it shold still be not mushy. The individual grains should still be visible and it is ok to see some of the grains having a bit of white parts at this point as it will continue to cook and expand in the oven.

Transfer the rice into the greased pan and spread out evenly. Pour the reserved latik syrup on spread evenly on top of the rice. Bake in a preheated oven at 350°F/180°C for 20-30 minutes or until the latik is reduced and becomes bubbly.

Remove from oven and let it cool down. Cut into squares and serve.