In a food processor or blender, puree pears. Transfer to a medium-sized saucepan and cook over medium-low heat, stirring almost constantly, until reduced to 1 cup, 10 to 15 minutes. (Adjust heat as necessary to maintain a gentle simmer). Transfer to a large bowl and let cool completely. Preheat oven to 350 degrees F. Lightly oil a 10-inch tube pan or coat with nonstick cooking spray. Dust with flour, shaking out excess. In a small saucepan, melt butter over medium heat. Cook, swirling the pan, until the butter turns a light, nutty brown, about 60 seconds. Pour into a small bowl, stir in oil and set aside. Sift cake flour, salt, baking powder and baking soda into a medium-sized bowl and set aside. Add 1 1/2 cups of the suger, buttermilk, vanilla, lemon zest, egg yolks and the butter-oil mixture to the reserved pear puree and whisk until smooth. In a clean mixing bowl and with clean beaters, beat the 4 egg whites until soft peaks form. While continuing to beat, slowly add the remaining 1/4 cup sugar and beat until stiff, but not dry, peaks form. With a rubber spatula, gently fold the dry ingredients into the pear puree mixture alternately with the beaten whites, making three additions of the dry ingredients and two additions of the beaten whites. Turn the batter into the prepared pan. Bake for 40 to 45 minutes, or until a cake tester inserted in the center comes out clean. Let cool in pan for 5 minutes, then turn out onto a rack to cool, right side up. Entered by: Diane Pahl (1:2410/120) Recipes from: Eating Well, The Magazine of Food and Health (tm) ISSN 1064-16399