Boil water in a large saucepan, add 2 tsp salt and 2 1/4 cups noodles, cook 10 minutes until just shy of al dente.
Reserve 3 oz pasta water before draining.
Preheat oven to 375F.
Melt 4 1/2 Tbsp butter in a large skillet over medium heat.
Add 3/4 diced shallot, 1 1/2 cloves minced garlic, and seasonings, cook 2-3 minutes until fragrant.
Add 4 1/2 Tbsp flour and stir continuously for 4-5 minutes to form a roux.
Slowly add 1 1/2 cups milk, stirring constantly until incorporated.
Add 1/3 cup stock and 3/4 cup heavy cream, whisk together.
Stir in 1 1/2 curry cubes and reserved pasta water until cubes melt completely.
Add 2/3 of the 15 oz grated white cheddar in two batches, stirring until melted.
Reserve remaining 1/3 cheese for topping.
Add cooked noodles to cheese sauce and stir to combine.
Transfer to greased oven-safe baking dish.
Top with remaining cheese and 3/4 cup breadcrumbs.
Place on baking sheet on middle rack and bake 15 minutes.
Switch to broil and watch closely until breadcrumbs are golden brown and crispy.
Let stand 1-2 minutes before serving.