Preheat the oven to 350F. Prepare loaf pan by spraying liberally with coconut oil or baking spray. In a small bowl, combine the cranberries with the 1 teaspoon of flour and toss to coat. Set aside.
In a stand mixer or large bowl, beat the butter and sugar together until smooth. Add in the eggs, beating between each one. Then add in the remaining 2 cups flour, salt and vanilla. Beat until combined, then carefully stir in floured cranberries and pistachios. Pour mixture into prepared loaf pan and lightly tap pan on the counter to release any air bubbles.
Bake for 1 hour 15 minutes - 1 hour 30 minutes, until golden brown and a toothpick inserted into the center comes out clean. Remove from the oven and let cool in the bread pan for about 30 minutes. Use a butter knife to release the bread from the sides of the pan, then flip upside down to release the bread and let cool fully on a baking rack.