This Creamy Brussels Sprouts au Gratin is the perfect holiday side dish!  Roasted brussels sprouts and pearl onions smothered and covered in a decadent, creamy gruyere cheese sauce and topped with a buttery, crunchy topping.  This brussels sprouts casserole is insanely delicious and guaranteed to become a family favorite!
*Updated*
This post was originally published in November 2014.  I?ve updated the post below to include new photos and more information about brussel sprout gratin.  Plus, I?ve included step-by-step photos to show you how easy brussels au gratin is to make! 
Hi friends!
Are you ready for the creamiest, dreamiest, most swoon-worthy side"
Todays dish just so happens to be my all time favorite vegetable side dish, especially for the holidays!  And, after you give it a taste, I’m confident you and your family will love it too! Brussels Sprouts Gratin
Roasted, tender brussels sprouts and sweet pearl onions smothered with creamy, rich béchamel sauce, then sprinkled with a crunchy panko breadcrumb, cheese and pine nut topping, and baked until golden brown and bubbly.
The brussels sprouts in this gratin are nothing like the memories you hold of your grandmother’s or mother’s sprouts.  You know those over-cooked, mushy, sad and lifeless sprouts.  These brussels sprouts are everything a side dish should be – perfectly cooked, flavorful, rich and highly addictive!!  Basically, this gratin is nothing short of sensational!
I pinkie...