1-Preheat the oven: Set it to 400 degrees Fahrenheit to get ready for baking.

2-Prep the bread: Slice the French bread loaf in half lengthwise and hollow out the centers to create space for the filling.

3-Sauté mushrooms: Heat 1 tablespoon olive oil in a skillet, add 1 1/4 cups cremini mushrooms, 1/2 teaspoon kosher salt, and 1/2 teaspoon black pepper. Cook until golden.

4-Cook aromatics: In 3 tablespoons unsalted butter, sauté 1 cup diced yellow onion and 1 minced garlic clove with the remaining salt and pepper until soft.

5-Brown the beef: Add 1 pound lean ground beef to the pan, cook until browned, then mix in the mushrooms.

6-Build the sauce: Stir in 3 tablespoons all-purpose flour and 2 teaspoons paprika, cook for 1 minute. Pour in 1 1/2 cups beef broth and simmer until thickened.

7-Finish the filling: Off heat, stir in 1 teaspoon Dijon mustard and 1/2 cup sour cream for creaminess.

8-Assemble: Divide the stroganoff mixture into the bread halves, top with 2 cups shredded Havarti cheese.

9-Bake: Place in the oven for about 15 minutes until cheese melts and bubbles.

10-Serve: Let cool slightly, cut into squares, and garnish with chopped parsley.