Preheat the oven to 400F.

Grease a 2 quart casserole dish and set aside. 

For this recipe you’ll need to make the sauce first. 

In a large saucepan melt 2 tablespoons butter. Slowly whisk in the flour and cook for a minute or so to thicken. Gradually whisk in the hot milk until thickened and boiling.

Remove the sauce from the heat, whisk in the mustard and 2/3rds of the shredded cheese. Season with salt and pepper and set aside. 

In a large frying pan, melt 2 tablespoons butter and saute the sliced fennel for 2-3 minutes until softened . Add the sliced mushrooms and saute for another 2-3 minutes until the mushrooms have softened as well. 

Slowly stir in 5 tablespoons of the cheese sauce. 

Pour mixture into the bottom of a 2 quart casserole dish and set aside. 

Place 2 tablespoons of flour, salt and pepper on a dinner plate and gently mix. Next coat the haddock pieces with the seasoned flour mixture. Lay the coated haddock over the mushroom and fennel mixture in the casserole dish. 

Arrange egg slices over the haddock and then pour the remaining sauce over the top. 

In a small bowl, mix the crushed crackers with the remaining ⅓ cup of grated cheese and sprinkle on top. Dust with paprika and bake in the middle of the oven for 30-35 minutes until the sauce is bubbling and the cracker crust is a golden color. 

Serve warm.