How to Make It
Preheat oven to 375°. Bring 3 qt. water to a boil in a stockpot or large saucepan. Add both packages of gnocchi and 1/4 cup kosher salt. Boil about 3 minutes or until gnocchi float.
Melt butter in a large saucepan over medium heat. Add shallots, and sauté 30 seconds or until fragrant. Add flour and chopped thyme, and cook, stirring constantly, 2 to 3 minutes or until mixture is golden brown and smooth. Gradually whisk in milk. Increase heat to high.
Bring mixture to a boil, whisking occasionally. Reduce heat to medium-low, and simmer, whisking constantly, 5 minutes or until slightly thickened and mixture coats the back of a spoon. Stir in mustard and hot sauce. Remove from heat.
Add sharp and extra-sharp Cheddar cheeses, and stir until melted. Stir in gnocchi and remaining 2 1/2 tsp. salt, and transfer to a lightly greased (with cooking spray) 11- x 7-inch or 2-qt. baking dish.
Bake at 375° for 25 minutes or until gnocchi is puffed and sauce is golden and bubbly. Increase oven temperature to broil, and broil 2 minutes or until top is slightly browned. Let stand 5 minutes, and serve immediately.
We tested with Gia Russa Gnocchi with Potato.