From: https://cooking.nytimes.com/recipes/1015109-skillet-macaroni-and-broccoli-and-mushrooms-and-cheese

Ingredients

• 4 oz grated Cheddar
• 2 oz grated Parmisan
• 1 tbsp butter
• 1 small yellow onion, diced
• 1 can tuna in oil
• 3 tbps flour
• 3 cups low fat milk
• 1 tbsp dijon mustard
• 1 tbsp dried thyme
• salt to taste
• black pepper to taste
• 8 oz dried pasta shells, cooked al dente
• 4 cups broccoli florets, blanched

Method

• Mix Cheddar and Parmisan in a bowl, set aside
• Melt butter in skillet, add onion and cook until tender
• Sprinkle flour in skillet until onion covered
• Whisk in milk until creamy, whisk in mustard, thyme, salt and pepper. Continue stirring until bubbling and thickened, about 3 minutes
• Remove from heat, stir in 3/4 of cheese until smooth, stil in pasta, tuna and broccoli
• Sprinkle remaining cheese on top, but under broiler for few minutes until browned
• Let cool before serving