Instructions: Meanwhile, spray or coat with nonstick spray a 9 inch spring form or cake pan at least 2 inches deep. You also may use an extra-deep, 9 inch tart pan with a removable bottom. Set aside the sprayed pan.

Preheat the oven to 350 degrees.

In a large bowl, combine the flour and sugar. Using your hands, a fork or a pastry blender, cut in the butter until the mixture is crumbly and mealy. Set aside 1/2 cup of this mixture for the topping.

To the remaining flour mixture, stir in the baking powder, baking soda, cinnamon, orange zest and salt. Stir in the egg, vanilla and buttermilk or sour milk to make a soft batter.

Spread two-thirds of the batter over the bottom and up the sides of the prepared pan. Spread the rhubarb puree on top of this batter. Dollop the remaining batter by teaspoonfuls over the rhubarb. Sprinkle the top with the reserved flour mixture.

Place the pan on a non-insulated baking sheet. Bake for 35-40 minutes or until the top is browned and a wooden pick inserted into the coffee cake comes out clean. Remove from the oven and cool well. When cool, dust with confectioners sugar if desired.

Makes 10 servings.

Cooks note: For best results, choose from the pan sizes mentioned and do not substitute. Sour milk is not the same as spoiled milk, which you should not use.

To sour milk, place 1 tablespoon of lemon juice or vinegar in a glass measure.

Pour milk to the 1 cup mark. Allow to stand 5 minutes to curdle. Use in place of buttermilk.

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