Tuna on Toast

4 Tbsp butter
4 Tbsp flour
2 cups milk
Dash salt
Dash white Pepper

1. In heavy saucepan over low heat, melt butter.
2. Stir in flour with a wire whisk.
3. Cook over low heat for three minutes, stirring constantly  Do not allow the mixture to brown.
4. Gradually stir in milk, whisking constantly.
5. Cook over low heat for 3-5 more minutes until sauce begins to thicken.
6. Add can of tuna
7. Add green peas.