Step 1: Make the Puree
Puree 1 pound of rinsed and hulled strawberries. You should have a little over 1 cup. Stirring occasionally, simmer the puree over medium-low heat until you’re left with 1/2 cup or slightly more (you need 1/2 cup for the cake). This takes at least 25–35 minutes, but could take longer depending on your pan or how juicy your strawberries were. Allow to cool completely before using in cake batter. You may want to make the reduced puree the day before so it has plenty of time to cool down. I cover and place in the refrigerator overnight. Allow it to come back to room temperature before adding to the cake batter.