Preheat the oven to 350°F (175°C) and grease two 9-inch cake pans. In a large bowl, beat butter, sugar, and oil until light and fluffy. Add eggs one at a time, mixing well. Stir in vanilla extract and strawberry purée.
In another bowl, whisk flour, baking powder, baking soda, and salt. Gradually add dry ingredients to the wet mixture, alternating with buttermilk, until just combined.
Divide the batter evenly between the cake pans. Bake for 28–30 minutes or until a toothpick inserted in the center comes out clean. Let cakes cool completely before frosting.
Beat butter until creamy, then gradually add powdered sugar. Pour in strawberry purée and vanilla extract, mixing until smooth and fluffy. Adjust consistency by adding more sugar if needed.
Spread a layer of frosting on one cake layer, place the second layer on top, and frost the entire cake. Garnish with fresh strawberries, slice, and enjoy!