Preheat oven to 350 degrees.
Spray 9x13 pan with cooking spray & set aside.
Combine all cake ingredients (except diced pears) in mixer bowl & beat until smooth batter forms.
Fold in diced pears.
Spread into prepared pan.
Take 1/4 cup of caramel & drop dollops on top of batter. Take a stick or knife & drag though to swirl. Reserve remaining 1/4 cup caramel for serving.
Add sliced pears to top- laying out across - not overlapping.
In separate small bowl combine streusel ingredients & mix with fork. This will be more of a creamy paste like consistency - not crumbly.
Drop in small spoonfuls on top of batter. Do not mix in.
Bake 45-50 minutes - until toothpick test is clean.
Cool in pan 45-60 minutes.
Drizzle remaining caramel over top when serving.