Butter a 9-inch springform pan. Heat oven to 350 degrees F.
Combine 3/4 cup sugar and cornstarch in medium sauce. Stir in rhubarb. Cook
and stir over medium heat until mixture comes to a boil and thickens. Cool and
set aside.
Stir together milk and vinegar; set aside.
Combine flour and remaining 3/4 cup sugar.
Cut in butter until mixture is crumbly and set 1/2 cup of mixture aside.
To remainder add baking powder, baking soda and nuts.
Combine egg and milk mixture and add to dry ingredients, stir until just
moistened.
Spread 2/3 of the batter over the bottom and sides of prepared springform
pan.
Spoon rhubarb filling over batter.
Drop remaining batter over rhubarb by
spoonful; sprinkle with reserved streusel mixture.
