Butter a 12 cup bundt pan and dust with flour.
In a medium bowl whisk together the flour, baking soda, baking powder and salt.
In the bowl of a stand mixer with the paddle attached cream the butter and sugar together until light and fluffy - about 3 minutes.
Add the eggs, one at a time mixing well after each addition.
Add the vanilla and mix well.
Add the flour mixture in thirds and buttermilk or sour cream/milk in halves alternating between the two beginning and ending with the flour mixture.
Fold in the pears.
Add half of the batter to the prepared pan.
Sprinkle in the streusel mixture, squeezing it to make chunks.
Top with the other half of the batter.
Bake in the preheated oven for 55 - 60 minutes until a toothpick or cake tester comes out clean.
If you are going to make your own salted caramel do it while the cake is baking. I have a recipe with a video on how to make salted caramel
Let the cake cool for 10 minutes and then remove the cake from the pan and cool completely.
When ready to serve, melt the chips and butter together.
Drizzle the cake with the chocolate, then the caramel then the chocolate again.