Roast cauliflower on a non-stick baking sheet at 400°F for about 10 minutes.
Meanwhile, melt butter and cream cheese over medium heat in a large pot.
Add heavy cream.
Add dijon mustard.
Add shredded cheeses.
Add crab. Stir.
Pour mixture over cauliflower.
Top with extra shredded cheese and bake at 400° for 20-25 minutes.
