Preheat oven to 350 degrees F. Line an 8 inch square metal pan with non-stick foil.
Thoroughly stir together flour, baking powder and salt. Set aside.
In a microwave-safe bowl, melt butter on high for 1 minute. Add brown sugar and stir well. Stir in the egg and vanilla and beat 15 strokes with a mixing spoon.
Add flour mixture to sugar mixture and stir just until mixed. Mixture will still be very warm so let it cool for 5 minutes. Stir in chips.
Bake for 25 minutes or until a toothpick inserted comes out clean and bars appear set (edges will be brown).
Stacy's Notes - First made these Feb 2008. I used everything as listed (except I don't have non-stick foil, just sprayed regular foil) and I used butterscotch chips from my freezer. These were really good! In my oven, these baked for 20 minutes at 350 degrees, then I turned the oven off and put them back in for the last 5 minutes. I did check with a toothpick at the end to make sure they were done. These bar cookies are pretty flat, but have a really good butterscotch-y flavor. I have a lot of butterscoth chips to use, but I do want to try them with other flavors of chips (like cinnamon and semi sweet). I've made these several times and we love them. They're a good size for us, 16 small squares in the 8" square pan.
NOTES : from Anna Ginsberg's blog. She said -- "This is a simple pan/bar cookie, but you can jazz is up by using different types of chips. I used a combination of cinnamon and chocolate chips, but you can use butterscotch, bittersweet chips, dark – whatever is on hand."
Yum, these are so good! I have doubled the recipe fine and baked it in a 9x13 glass pyrex pan, maybe 30 minutes? I watch it to make sure it's not getting over baked. Tried a mixture of butterscotch chips and chocolate chips, it turned out good.
It looks like it won't be enough batter to fill up a pan but it seems to spread to fill it up ok the times I've made these.