Why does my Heavy whipping cream pound cake have an aftertaste between flour and metallic? 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 &quot;lighter&quot; 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 &quot;vanilla flavoring&quot; in baked goods because it can include things that are not vanilla pods and ethanol, which can also create off flavors.