Cut the bread into large pieces. You can trim off the crust, but I didn't. I feel like it's a waste to trim them off since we will be blending them anyway. Put them inside the blender with milk, water, condensed milk, and eggs. Blend until smooth
Combine all ingredients for agar agar in medium-large pot. Bring it to a simmer and then cook until agar agar and sugar dissolves. You shouldn't see any more specks of agar agar powder. This is important or your pudding won't set later. Lower the heat and add the bread mixture into the pot and keep stirring and cook until just slightly thickened, it just coats your spatula thinly
Assembling:
Wet the loaf pan with water and then drain off excess water.
Divide 250 ml of the mixture into one container (preferably with a spout so it's easier to pour) and add cocoa powder. Then 250 ml into another container with a spout and add ube extract or any color or extract you wish. If you don't have any container with a spout, you can use a spoon too. Leave the rest of the white mixture in the pot
Pour 1/3 of the white mixture into the pan, covering the base of the pan. Then pour 1/2 of the chocolate mixture in the middle (as shown in the photo above). Then 1/3 of the white in the middle, then 1/2 of the purple
Repeat again with the rest of the white mixture, pour in the middle. Then follow by the rest of the chocolate, pour in the middle, then purple. This is just the order of the color I did, you can do it however you like
Use a skewer or chopstick to create a marble effect. You can run it up and down to create that effect. No hard and fast rule here
Chill:
Let this chill in the fridge for at least 4 hours or overnigh
Unmolding:
The pudding will detach from the pan if you gently shake it. Alternatively, you can run a knife around the edge to release. Put a rectangle shape plate or cutting board on top of the pan and invert and then slice into serving portions