In a large skillet or saute pan, bring the butter over medium high heat until melted. Add the dry orzo and stir to coat. Cook for 2-3 minutes or until some pieces of the orzo begin to brown. Add the minced garlic and stir together. Cook for an additional minute or so until garlic is fragrant. Add the broth and water to the pan and bring to a boil. Cover the pan and reduce heat to a simmer. Allow to simmer for 5 minutes and then stir in the broccoli, Replace the lid and continue to simmer for an additional 8-10 minutes until the broth is absorbed and the orzo and broccoli are tender. Remove from heat and add the cheddar, mustard powder, parsley, salt and black pepper and stir together until thoroughly combined. Serve immediately.