The first step is to gather all of your ingredients and preheat your oven to 350 degrees. You will need a parchment lined 8x8" baking tray.
Start by combining your soft butter and brown sugar together in an electric mixer on medium speed. By soft butter, I mean butter that you threw in the microwave for maybe 10-15 seconds but that is not completely liquid.
Once the butter and sugar have creamed together, add in your egg yolks, vanilla and salt. Mix until just combined.
In a separate bowl, combine flour with baking powder and mix. Gradually add this to your wet mixture on low speed until combined.
Add your sprinkles and M&M's to the mixer last, allowing it to mix on high speed for just a few seconds to crush up the M&M's!
Transfer 3/4 of this mixture to your parchment lined baking dish and spread it out evenly. Layer in your oreos 4x4, you should be able to fit about 16 oreos across the top. Spread the remaining 1/4 of the batter in dollops across the top. You are going to spread this out half way through baking so don't worry about it being perfect!
Stick this in the oven and set your timer for 10 minutes. At the 10 minute mark, pull the blondies out of the oven and use the bottom of a stainless spoon to move the melted, partially cooked batter across over the top of the oreos. This helps it to get all in between the oreos and cook perfectly! You can add more sprinkles and your crushed candy cane at this point.
Stick these back in the oven for another 12-15 minutes until the edges are golden and the middle looks set.
Let these cool before slicing in to them. Makes 16 bars!
