Created by Cupcake33 on July 23, 2015
Step 1: In a saucepan over medium heat, heat water, butter and 1é2 teaspoon salt until the butter is melted. Add flour all at once and vigorously stir for about 2 minutes, until smooth. Remove from the heat and place in an electric mixer with paddle attachment. Let it sit for 3 minutes, stirring to cool.
Step 2: Beat on medium-high and add eggs one at a time until fully incorporated. Add the dry mustard and beat until the dough is smooth. Cover with a towel while making sauce.
Step 3: Melt butter in a saucepan over medium heat. Add flour and cook, stirring constantly for about 2 minutes until it has thickened but is not brown. Gradually whisk in the milk, adding slowly and stirring constantly to avoid lumps. Decrease heat to low and cook for 6 minutes, stirring often until it is thick. Remove from heat and add salt, cayenne and 1/2 cup gruyere, stir until cheese is melted.
Step 4: Butter a shallow baking dish and sprinkle half of the parmesan over the bottom and sides. Spread 1 cup of sauce over the bottom of the dish.
Step 5: Bring a large pot of salted water to a boil. Using a small ice cream scoop, scoop a generous 1 tablespoon scoop of dough and drop into the water. Add about 8-10 balls at a time. Cook for 2 minutes and remove to a paper towel lined plate. They will only be partially cooked. Continue with remaining dough.
Step 6: Preheat oven to 350º and place oven rack in the top third of the oven.
Step 7: Place gnocchi in a single layer on top of the sauce in the prepared dish. Spoon the rest of the sauce over the gnocchi and top with remaining gruyere and parmesan.
Step 8: Bake for 15 minutes. Increase the oven temperature to 400º and cook an additional 15-20 minutes until top is slightly browned. Let cool for a few minutes before serving.