Preheat the oven to 350°F and line  24 cup mini muffin tins with liners
In a medium mixing bowl, sift together the flour, baking powder, baking soda, pumpkin pie spice and salt.
In a separate bowl, beat together the melted butter, sour cream, brown sugar, mashed bananas, egg and vanilla. Beat with the mixer for 2 minutes until combined.
Add the dry ingredients into the wet ingredients until all of the ingredients are incorporated. This will only take around 2 minutes. Stop and scrape the bowl periodically while mixing so all of the ingredients will combine.
Fold in ½ cup mini chocolate chips and ½ cup toffee chips by hand.
Divide the batter evenly among the muffin cups using a teaspoon or a 1 ounce ice cream scoop.
Sprinkle the remaining chocolate chips and toffee bits on top.
Place the pans into the oven and bake for 15-17 minutes until golden and a toothpick inserted into the center comes out clean.
Remove from the muffin tins and cool completely on a wire racks.
I was able to yield 42 mini muffins from this recipe but, this depends on how generous you are when you divide the batter. This recipe will easily make 36 mini muffins.