In a large mixing bowl, combine the heavy whipping cream and powdered sugar.
Whip the mixture using a hand mixer or whisk until it reaches a thick, smooth consistency similar to whipped cream. It should hold its shape but still be soft and creamy.
Divide the whipped cream evenly into three separate bowls.
Leave one portion plain for the classic cream filling.
Gently fold the Biscoff spread into the second portion until fully combined and smooth.
Fold the Oreo crumbles into the third portion until evenly distributed.
Heat oil in a frying pan over medium heat until hot but not smoking.
Carefully place each slice of milk bread into the hot oil and fry until golden brown on both sides.
Remove the bread from the oil and place on paper towels to drain excess oil.
Allow the bread to cool slightly until warm but not hot to the touch.
Slice each piece of bread diagonally in half.
Using a knife, carefully cut a pocket into the center of each piece without cutting all the way through.
Transfer each cream filling into a piping bag or zip-top bag with the corner snipped.
Pipe the plain, Biscoff, and Oreo creams into the bread pockets, filling generously.
Serve immediately for the best texture, or chill briefly for a firmer cream filling.