Blend butter, 1 cup brown sugar, egg and vanilla together. In separate bowl mix flour, baking powder and salt. Add dry ingredients to first mixture. Add pecans. Spread in 8 inch pan and bake in 350 oven for approx. 25 minutes.
When baked cover with miniature marshmallows (put on hot cake and return to oven to soften. Press to flatten).
Put 1 cup brown sugar, milk and 1 tbsp. butter in saucepan on stove and bring to a boil. Boil for 1 minute and immediately add 1 cup icing sugar. Beat until spreading consistency.
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