Easy Apple Custard Pie

• 72 b -crust
• 9 glass pie (plate)
• 4 egg whites
• 2 eggs
• 1/4 around the edge
• 260 gr firmly packed brown sugar
• 230 ml sour cre sour cream (light)
• 220 gr all purpose flour
• 170 gr margarine
• 160 gr rolled oats (uncooked)