2. In a 3-quart saucepan, heat butter to melt and cook onion until tender; do not brown.
3. Stir in flour and keep stirring until bubbly.
4. Blend in soup.
5. Slowly add milk and stir until mixture is smooth.
6. Remove 2 cups crushed potato chips and keep aside.
7. In the bottom of two 13x 9x2-inch metal baking pans, alternately spread layers of remaining potato chips, salmon, peas and soup mixture.
8. Top with reserved chips.
9. Bake in preheated oven for about 40 to 45 minutes until dish is heated through.
10. Serve Salmon And Potato Chip Casserole with a green salad.