Line a baking sheet with parchment paper and set aside.
Place whole Oreo cookies in the bowl of a food processor and pulse until no chunks remain.
Add the banana chips and continue pulsing until the mixture is fine, like the texture of sand.
In a medium-sized bowl, mash the bananas with a fork and add the cream cheese. Using a hand-held mixer, blend on high speed until smooth.
Fold the cookie/banana chip crumbs into the cream cheese mixture until a paste-like ball is formed.
Refrigerate the dough mixture for 1 hour.
Scoop small amounts of the dough using a small cookie dough scoop and place them on the parchment-lined baking sheet.
Shape the mounds of dough so that smooth balls are formed and freeze them for 2 hours until firm.
Heat the white chocolate in a microwave-safe bowl, (in 30-second intervals), stirring between each interval until the chocolate has melted and is smooth. Add the vegetable oil and stir until well blended.
Using a fork, dip a frozen ball into the melted chocolate until submerged. Tap any excess candy on the side of the bowl and place the chocolate-covered truffle on a parchment-lined baking sheet.
Crush the walnuts and sprinkle on each truffle before the white chocolate sets.TIP - It’s important to work quickly when sprinkling the walnuts over the truffles. If you find the chocolate has already set, dab a bit of melted white chocolate on the truffle and then add the walnuts to that.
Only use brick-style cream cheese in this recipe, otherwise the texture won’t be the same.
You should soften your cream cheese before beginning which means you should let it rest on the counter until it reaches room temperature. To speed up the softening process you can cut it into cubes while it rests. Properly softening your cream cheese will make combining it with the other ingredients a lot easier, plus, you won't get clumps or pockets of cream cheese throughout the filling.
You will need about 2 ripe bananas to yield 1 cup mashed. Make sure to use ripe bananas so they are sweet and easily mashable.
You can stick to white chocolate or switch it up with dark, milk, or semi-sweet chocolate for the coating.