All of my dry and wet ingredients were perfectly measured and at room temperature.   I did not use baking powder as the recipe did not require it.  I substituted vanilla extract (McCormick) for vanilla flavoring (McCormick).  I baked the cake in the oven on 325 in a pre-heated oven for 90 minutes, let it cool for 20 minutes, and then removed it from the baking pan and onto a cooling rack for 3 hours.   Otherwise the cake baked perfectly and was delicious until I finished the first slice.  The recipe was as follows: Ingredients  1 ½ cups (3 sticks) of salted butter, softened 3 cups of white granulated sugar 6 large eggs (room temp.) 3 cups of sifted Swans Down Cake Flour ½ tsp of vanilla extract ½ pint of Heavy Whipping Cream 2 cups of sifted powdered sugar ¼ cup (½ stick) of butter, melted 2–4 Tbsp of heavy cream Extract/flavoring, if desired  Steps:  Preheat oven to 325°F. In large mixing bowl, cream butter then gradually add sugar beating on medium speed until creamy. Add eggs, one at a time, beating just until blended after each addition. Add Swans Down Cake Flour and heavy whipping cream alternately beating on low speed until just blended as over beating will yield a dry and heavy cake. Add vanilla; for richer flavor, add additional 1 ½ tsp. vanilla extract. Pour into prepared pan Bake 90 minutes  
I think SuperWild1 is on the right track here. Some people get a strong metallic taste from cornstarch, and its presence in this recipe might be doing strange things to the flavor. I'm not even sure why powdered sugar is in this recipe - nor cake flour, for that matter. Seems someone might have been trying really hard to make a "lighter" pound cake...? Anyway, if you want to try this recipe again, you can either make your own powdered sugar in a food processor, or you can use the same amount of caster (or ultrafine) sugar and see how that works for you. Also, be careful with "vanilla flavoring" in baked goods because it can include things that are not vanilla pods and ethanol, which can also create off flavors. 