Eggs Benedict Casserole

Name: Eggs Benedict Casserole
Ingredients: 6 English muffins, split and cut into 1 inch pieces; 1 Tablespoon olive oil, plus more for greasing; 1 large leek, dark green part removed, cut into 1/4 inch half moons; 12 Ounces Canadian bacon, chopped; 6 large eggs, at room temperature; 2 1/2 Cups whole milk; 1 1/2 Teaspoon dried mustard; 1 1/2 Cup heavy cream; 2 Tablespoons fresh chives, plus more for garnish; 1/2 Teaspoon cayenne pepper; Salt and pepper, to taste; 1 stick butter; 8 egg yolks, at room temperature; 1 Tablespoon fresh lemon juice; 1 Teaspoon Dijon mustard; 1/2 Cup heavy cream; 1/2 Teaspoon salt; 1/4 Teaspoon cayenne pepper