Preheat oven to 350 degrees F (180 degrees C) and place the oven rack in the middle position. Butter and flour (or spray with a non stick vegetable/flour spray) the bottom and sides of an 8-cup loaf pan (9 x 5 x 3 inch) (23 x 13 x 8 cm).  Set aside.

Place the walnuts (or pecans) on a baking sheet and bake for about 8 minutes or until brown and fragrant. Remove from oven and let cool completely before chopping coarsely. Set aside.

In the bowl of your electric mixer, or with a hand mixer, beat the butter until softened (about 1 minute). Add the sugar and continue to beat until light and fluffy. Add the eggs, one at a time, beating well after each addition. Beat in the vanilla extract. In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and ground cinnamon. 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. Mix only until combined. Gently fold in the chopped strawberries and walnuts. 

Scrape the batter into the prepared pan and bake about one hour, or until the bread is golden brown and a toothpick inserted in the center comes out clean. Place on a wire rack to cool and then remove the bread from the pan. Serve warm or at room temperature.

Makes 1 loaf.

Sources:

Junior League of Portland, Oregon. Portland's Palate. Portland, Oregon: 1992.

Mushet, Cindy. Baking with the American Harvest Newsletter. California: 1994.