Preheat the oven to 350°F and grease a 9×9 baking dish with 1 teaspoon butter. Set aside.

Melt the remaining 2 tablespoons butter in a sauté pan over medium-high heat. Add the onions with a light sprinkle of salt and pepper. Cook for 2 minutes until softened and fragrant.

Sprinkle in the flour and stir constantly for 1 minute to form a paste. Slowly whisk in the milk until smooth. Simmer for 4–8 minutes until thickened and creamy. If lumps appear, whisk vigorously until smooth.

Stir in the thawed peas and season with more salt and pepper if needed. Pour the mixture into the prepared baking dish.

Mix the panko breadcrumbs with Emeril’s Original Essence in a small bowl. Sprinkle over the peas, then top evenly with shredded cheddar cheese.

Bake for 20–25 minutes until hot and bubbly with melted golden cheese and crisp breadcrumbs. For extra browning, broil for 1–2 minutes at the end while watching carefully.

Let the casserole rest for 5 minutes before serving so the sauce can settle slightly. Serve warm while the topping is still crunchy and the cheese stays gooey.