Corned Beef with Cabbage without sprinkles bouillon

1 egg yolk 1/2 teaspoon dry mustard 1 pinch cayenne pepper 1 tablespoon water 1/2 cup butter , melted and warm (1 stick) 2 tablespoons lemon juice kosher salt[...]

1/2 cup whole grain Dijon mustard 1/8 cup mayonnaise (optional, if using mayo you may want to cut the mustard back to 1/3 cup) 2 teaspoons capers 1/8 cup[...]

8 ounces medium egg noodles 4 tablespoons butter , divided 1 cup chopped onion 2 1/2-3 cups diced corned beef , about 12 ounces 16 ounces frozen chopped[...]