Melt butter in pan and saute next 4 ingredients for 2-3 minutes. remove from pan. melt butter, add flour, cook 1-2 minutes.
Remove from heat, gradually add milk, salt and pepper.
Return to heat and stir constantly till mixture boils and thickens.
Simmer over low heat 5-7 minutes.
Add next six ingredients and mix well, beat egg whites till stiff, fold into sauce mixture.
Pour third of the sauce mixture into 4 souffle dishes, sprinkle over half the mushroom mixture. repeat layer of sauce and mushroom and end with a sauce layer and sprinkle with cheese.
Bake at 190 degrees c for 30-35 minutes.