Cauliflower and Broccoli Gratin

This is a recipe a got from a lady at church.  She brought it to a potluck and it was a hit.  Very delicious! -Kristin

5 cups cauliflower
5 cups broccoli
2 cups milk
1/4 cup and 1 Tablespoon butter, divided
1/3 cup flour
2 teaspoon dry mustard
3/4 teaspoon salt
1/4 teaspoon pepper
dash of cayenne
1/2 cup Panko crumbs
2 cups shredded cheddar cheese

• Preheat oven to 425 and grease a 9x13 pan.
• Cook cauliflower and broccoli in salt water for about 3 minutes or till almost tender.  Remove from heat and drain.  Then put the veggies in the 9x13 pan.
• Microwave milk for 2-3 minutes till steaming hot but not boiling.
• In a saucepan melt 1/4 cup butter and whisk in the flour until smooth.  Cook 30 seconds, whisking continually.
• Whisk in the hot milk and return to a boil.  Reduce heat and simmer for 5 minutes or until thickened.  
• Whisk in the salt, pepper and cayenne.
• Pour the milk mixture over the vegetables.
• Top with cheese.
• Melt the remaining 1 Tablespoon of butter and mix in the Panko crumbs.  Sprinkle over the cheese.
• Bake uncovered for 30-40 minutes.