Place the berries into a pan with the lemon juice and cook on medium low heat. Mash with a spoon and stir until mixture is reduced by half.
To Make the Cake:
Cream the butter and sugar.
Mix in all of the wet ingredients.
Whisk the dry ingredients together in a large bowl.
Using a stand mixer slowly add in the dry mixture to the wet mixture and mix until combined.
Transfer a cup of the batter to a small bowl and stir in 3-4 tablespoons of the raspberry reduction.
Pour into papered cupcake pan, add a heaping tablespoon of the raspberry flavored batter.
Bake at 350F for about 15 minutes.
Notes
I made a batch of the cupcakes flavored with the 3 tablespoons of the raspberry reduction but they turn lilac after baking. Not the end of the world but wasn't the look I was going for.
You can substitute whole milk yogurt for the sour cream if desired, I do it all the time and can’t really tell the difference.
Making the raspberry reductions takes a minute or two so if you're in a hurry try adding in some strained preserved or a bit or the juice from frozen raspberries instead.