Preheat the oven to 350°F and line a 12-muffin tin with paper cupcake liners.
Into a large bowl, whisk together the oat milk and apple cider vinegar. Set aside for 5 minutes to thicken slightly.
Add the sugar, oil, vanilla bean paste, and almond extract. Using a hand mixer, beat on medium speed to combine.
In a medium bowl, combine the flour, cocoa powder, baking soda, baking powder, and salt.
To the sugar mixture, add half of the flour mixture. Continue mixing just until blended.
Add the remaining flour mixture and beat, scraping down the sides of the bowl as needed, until fully incorporated.
Stir in the coarsely chopped Oreo cookies.
Pour the batter 3/4 of the way into each of the 12 liners.
Bake 20 minutes, or until a toothpick inserted in the center comes out clean.
Transfer to a cooling rack.
Once the cupcakes are cooled completely, prepare the Vanilla Buttercream Frosting as directed.
Into the prepared frosting, stir the remaining finely chopped Oreo cookies.
Top each cupcake with frosting and serve.