Cook the pasta according to package directions. Drain and set to one side.
1 pound dried fusili pasta
While the pasta is cooking, you can move on with the rest of the recipe.
Heat the oil on a medium high heat on the stovetop. Once hot, add the mushrooms, and a little salt and pepper, and cook til browned.
1 tablespoon oil, 1 pound white mushrooms, salt and black pepper
Once browned, add in the spinach a handful at a time and stir to wilt it. Set to one side.
9 ounces baby spinach
Preheat the oven to 360F / 180c.
To make the blue cheese sauce, heat the butter and oil in a skillet on a medium heat. Once melted, add in the onions, garlic, salt and black pepper. Cook to soften the onions, there is no need to color them.
2 tablespoons butter, 1 tablespoon oil, 2 Spanish onions, 4 garlic cloves, ½ teaspoon salt, black pepper
Add in the cream and blue cheese. Bring to a low simmer, and let cook for 20 minutes, stirring occasionally.
2 cups 35% cream, 4½ ounces Danish blue cheese
Meanwhile, place the breadcrumbs in a bowl.
½ cup panko breadcrumbs
Put the butter, oil and garlic in a small pot on a low heat and let the butter melt.
2 tablespoons butter, 1 tablespoon oil, 2 garlic cloves
Pour the garlic butter over the breadcrumbs and mix well to coat.
Place the cooked pasta into a casserole dish. Add the cooked spinach and mushrooms and pour over the sauce. Mix together so that everything is well combined. Sprinkle the breadcrumbs on top.
Place in the preheated oven and bake for 30 to 40 minutes til the breadcrumbs are golden brown and the sauce is bubbling.