Preheat oven to 350 degrees and prepare 2 cupcake pans.

Sift flour, salt, and baking soda in medium bowl.

In bowl of mixer, cream butter and sugar until fluffy. Add eggs one at a time until combined. Add buttermilk, oil and vanilla until combined. Add flour mixture and stir until just combined. Fold in berries.

Fill cupcake pans 3/4 way. Bake for 20 minutes. Allow to cool completely before frosting.

Icing:

Use a mixer to beat butter until light and fluffy. Add in powdered sugar a little at a time until you reach a slightly stiffer consistency then you wanted. Blend the strawberries into the mixture. The strawberry juices should thin out your buttercream a little bit, add more powdered sugar if needed.