1. Preheat oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.
2. In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla.
3. In a separate bowl, whisk together the flour, baking powder, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Stir in the butterscotch chips.
4. Pour batter into the prepared pan and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.

Caramel Glaze:

1. In a saucepan, melt butter and brown sugar over medium heat. Bring to a boil and cook for 1 minute, stirring constantly.
2. Remove from heat and stir in milk and vanilla extract. Gradually add powdered sugar, beating until smooth.

Crispy Topping:

1. In a bowl, combine Rice Krispies, pecans, and melted butter.

Assembly:

1. Let the cake cool slightly. Pour caramel glaze over the warm cake. Sprinkle with crispy topping.
2. Let the glaze set before serving.