My German grandma came to the U.S. in the 60's to help my mom take care of my brother and I. On her later visits she taught me how to bake some of her specialties. This cheesecake has always been a favorite.
Set out butter to soften in a medium sized bowl and cream cheese in a large bowl. Preheat oven to 375 degrees. Grease and flower spring form pan with flat bottom.
Mix streusel ingredients. Best done by hand until they form a crumbly texture and hold together somewhat when squeezed. Use half of streusel to line bottom and up 1.5 inches of sides of spring form pan. Reserve remainder for the top of cheesecake.
Add egg yolks, pudding mix, and sugar to softened cream cheese. Mix with blender until creamy. In separate small bowl beat egg whites until stiff. Add to creamy cheese mixture along with drops of extract and fold in gently. Do not mix in completely, but just enough so whites are still slightly visible as streaks through the cheese mixture. Pour into prepared crust.
Sprinkle remaining half of streusel mix over top of cheese mixture, squeezing to create crumbly clumps. Place in center rack of oven and bake for 45-60 minutes until center of cake cracks slightly and appears firm. The cheese and streusel should have a nice golden brown color.
Cool for 30 minutes in pan, then remove ring and cool for additional 30 minutes before attempting to remove the cake to a pedestal or platter. Can be served with fruit topping but also delicious plain. Can be served at room temperature or chilled.