Preheat oven to 350 degrees F.
Grease a 13x9x2 inch ovenproof pan.
Combine and crumble Streusel ingredients (sugar, butter, nuts, and flour)
In large bowl, combine fruit, water, lemon juice, 1 C. sugar, and cornstarch.
Microwave on "High" until thick and boiling (about 5 minutes), stirring occasionally. Set aside to cool.
Mix flour, remaining 1 C. sugar, baking powder, salt, cinnamon, and mace.
Cut butter into flour mixture.
Combine eggs, milk and vanilla in a separate bowl. Add to dry ingredients just until blended.
Spread 1/2 the batter in prepared pan.
Cover with fruit mixture, then spread with remaining batter.
Sprinkle with streusel topping mix.
Bake in preheated oven for 50 minutes or until done in center.
Easy - and fantastic!