This Magnolia Bakery Banana Pudding Recipe has layers of creamy pudding, bananas, and Nilla wafers. It's heaven and way easier than you think! This is the ACTUAL banana pudding recipe from their cookbook.
The reason the recipe says to serve within 8 hours is that the bananas will turn brown as they oxidize. There are a couple of things you can do to make not brown as fast:
1) Brush them with some lemon juice. Any fruit juice helps (pineapple, apple, orange). This can change the flavor slightly so brushing them is better than soaking them. Even water neutralizes the ph and will slow down the browning if you rinse them in water.
2) Rinse them with club soda. The advantage here is that it won't affect the taste. Don't use tonic as it has a bad taste.
3) Try to keep them airtight. The less contact with the air the less they will brown.
Source: Magnolia's Bakery Cookbook