Combine undrained pineapple, 1/4 cup sugar and 1 Tbs. flour in saucepan; cook, stirring constantly, until mixture is thickened and clear. Lightly beat 1 egg; stir part of hot mixture into it, then mix with remaining hot mixture in saucepan. Cook, stirring, 2 minutes longer. Set aside. Mix 3/4 cup flour with baking powder, salt, oats, brown sugar and 1/4 cup melted margarine. Press into buttered 8-inch square pan; bake at 375 degrees, 10 minutes. Mix remaining 1/4 cup melted margarine, remaining egg and remaining 1/2 cup sugar with toasted almonds. Spread pineapple filling evenly over baked crust; spoon almond mixture over the top. Bake at 375 degrees, 30 minutes longer.
Cool and cut into bars.