Preheat the oven to 350˚F. Line an 8x8 baking pan with parchment paper. Set aside.
In a large microwave safe bowl, melt the butter and the chocolate in 30 second intervals, mixing until smooth.
Mix in the egg and condensed milk. Slowly mix in the flour until fully incorporated. Fold in the crushed Oreos and sprinkles.
Pour the batter into the prepared baking sheet and press the chunks of Oreos on top.
Bake in the preheated oven for 30 minutes. Remove and allow the blondies to fully cool before cutting into squares.