Combine all streusel ingredients in a bowl and mix until the butter is incorporated. Do not overmixyou want a crumbly texture. Set aside. Grease an 8- inch round spring-form pan with butter. Set aside. Toss the apples, pear, brown sugar, and zest together in a small bowl and set aside. Dust the surface of the refrigerated dough with flour and cut off a 1-pound (grapefruit-size) piece. Divide the dough in two equal pieces, dust with more flour and quickly shape them into rough balls. Press the first piece of dough into the spring-form pan. Top with half of the apple and pear mixture, then sprinkle half of the streusel topping over it. Repeat with the next layer of dough, apple and pear mixture, and streusel. Allow the cake to rest for 60 minutes. Preheat the oven to 350°F. Bake the cake in the middle of the oven for 55 minutes. Allow to sit for about 15 minutes, then remove it from the spring-form pan. Allow to cool before serving.