I learned from various websites that corned beef can be very salty, especially when baked. To remedy this, place the corned beef in a large pot of water and boil over high heat for a minute. Drain the water and pat the corned beef dry.
Preheat the oven to 350 degrees. Layer a large piece of foil in a baking pan, then place the corned beef fat-side up on top of the foil.
Combine the mustard and honey and mix until well combined. Pour ¼ of the sauce into a serving dish and set aside for dipping.
Spread the remaining honey mustard mixture evenly over the corned beef. Next, sprinkle the brown sugar evenly on top.
Wrap the corned beef with foil, keeping space between the meat and the foil.
Place into the oven and bake for 2 hours.
Open the foil and broil the corned beef for 2-3 minutes, until the top is bubbly and lightly browned. Watch carefully so it doesn't burn.
Let the corned beef rest for at least 10 minutes before slicing across the grain.
Serve with the reserved honey mustard sauce. Enjoy!