1 ½ cups elbow macaroni
3 tablespoons butter
3 tablespoons all-purpose flour
2 cups milk
1 cup shredded extra-sharp Cheddar cheese
1 cup shredded Monterey Jack cheese
⅓ cup dill pickle relish, well drained
¼ cup minced onion
1 teaspoon chile-garlic sauce (such as Sriracha®)
salt and ground black pepper to taste
1 slice bread
1 teaspoon butter
Preheat the oven to 350 degrees F (175 degrees C). Spray a 1 1/2-quart casserole dish with cooking spray. Bring a large pot of lightly salted water to a boil. Cook elbow macaroni in the boiling water, stirring occasionally, until tender yet firm to the bite, about 7 minutes, making sure not to overcook. Drain and set aside. While the macaroni is cooking, melt 3 tablespoons butter over medium-low heat in a large saucepan. Blend in flour and cook, stirring constantly, until mixture becomes paste-like and light golden brown, about 5 minutes. Gradually whisk in milk and bring to a simmer over medium heat. Cook and stir until thickened, 10 to 15 minutes. Mix in Cheddar cheese and Monterey Jack cheese; stir until melted. Add dill pickle relish, onion, Sriracha sauce, salt, and pepper to cheese mixture. Stir in cooked macaroni. Pour mixture into the prepared casserole dish. Butter both sides of bread and tear into large pieces. Blend in a food processor or electric blender until you have crumbs. Spread on top of casserole.