1. Preheat oven to 350F degrees and place the oven rack in the middle position.
2. Spray the bottom and sides of an 8-cup loaf pan (9 x 5 x 3 inch) with nonstick cooking spray.
3. In the bowl of your electric mixer, or with a hand mixer, beat the butter until softened.
4. Add the sugar and continue to beat until light and fluffy.
5. Add the eggs, one at a time, beating well after each addition.
6. Add in the vanilla extract. Scrape down the sides of the bowl as needed.
7. In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and ground cinnamon.
8. With the mixer on low, add the flour mixture (in three additions) and sour cream (in two additions) alternately, starting and ending with the flour.
9. Mix only until combined.
10. Gently fold in the chopped strawberries and walnuts.
11. Scrape the batter into the prepared pan and bake about 1 hour, or until the bread is golden brown and a toothpick inserted in the center comes out clean.
12. Place on a wire rack to cool and then remove the bread from the pan.
Serve warm or at room temperature. This bread can be frozen.