Preheat oven to 375 degree. Butter 13x9 casserole dish

Bring large pot of salted water to boil. Carefully add cauliflower florets

Cook 7-8 minutes until fork tender. Drain well

Rinse cannelli beans and add to bottom of casserole dish

Add drained cauliflower to top of cannelli beans

Meanwhile in medium sauce pan melt butter on low heat

Once butter is melted stir in cornstarch until thickened slightly into roux

Add mustard, garlic powder, cayenne pepper, salt & pepper

Stir in half & half and continue stirring until mixture thickens slightly

Add greek yogurt and continue stirring a few more minutes

Add ¾ cup of the grated cheese mixture(montery jack & cheddar) and continue cooking till cheese is melted

Remove sauce from heat and pour over the cauliflower and cannelli beans

Mix gently to coat cauliflower and beans

Top with freshly grated parmesan cheese and fresh dill

Bake in preheated oven 35-40 minutes until bubbly and slightly browned on top

Allow to sit 10 minutes prior to serving