Preheat your oven to 350F or 180C. The flan is baked in the water bath. We need two baking pans. One pan is to hold the flan mixture, and another one should be big enough to hold the flan baking pan. Have both the pans ready. For the flan baking pan, you will need a 9 * 2 inch round pan or 8 * 8 * 2-inch square pan or 10 inch Angle Food Pan to make the flan for the mentioned quantity. For the large pan, I chose a roasting pan.

Prepare caramel - Heat sugar in a dry thick bottomed pan over medium heat until sugar dissolves. Swirl the pan often to avoid sugar clumps and get the sugar caramelized equally on all portions.

Once it turns golden brown, add the hot water and let it cook. It will bubble up and be very careful. Stir until it thickens a bit and it's completely dissolved. Switch it off then. Pour the caramel into the baking pan. Leave it for some time so that the caramel is crystallized.

Add the condensed milk, milk, eggs and vanilla extract to a large blender jar. Blend for a few minutes until smooth. If you can't fit all the ingredients in the blender, divide them equally into two batches. Pour the flan mixture into the baking pan and cover with foil.

Fill the large baking pan halfway through with water and place the pan with flan mixture inside it. Bring it to the oven and bake it in bain marie for 1 hour and 30 minutes or until the top is golden brown. Wiggle the pan a bit to see if it's still liquidy. If it's liquidy, leave it for an extra 15 minutes. You can also insert a cake tester to check. It should come out clean or almost clean.

Let the flan cool and transfer it to the fridge to cool overnight. To remove the flan from the mold, just run a straight spatula or knife along the sides and then carefully flip it on a plate. Enjoy :)