Preheat oven to 350°F Spray one 9×5-inch loaf pan with floured cooking spray, or grease and flour the pan; set aside.
In a large bowl, add 2 cups + 2 tablespoons flour, sugars, baking soda, optional salt, and whisk to combine; set aside.
In a medium microwave-safe bowl or glass measuring cup, melt the butter, about 45 seconds on high power. Allow butter to cool momentarily so you don’t scramble the egg.
To the butter, add the egg, buttermilk, oil, vanilla, and whisk to combine.
Pour wet over dry and stir until just combined; don’t overmix. Batter will be somewhat lumpy and don’t try to stir the lumps smooth or bread will be tough; set aside.
In a medium bowl, add the raspberries, 2 tablespoons flour, and toss lightly to combine (coating berries in flour helps to reduce sinking while baking).
Add the raspberries to the batter and fold very lightly to combine.
Turn batter out into prepared pan, smoothing the top lightly with a spatula and pushing it into corners and sides as necessary.
Bake bread for 45 minutes to an hour. Bread is done when top is set in the middle, slightly domed, springy to the touch, and a toothpick inserted in the center (if you can find a patch without hitting raspberries) comes out clean or with a few moist crumbs, but no batter.**.
Allow bread to cool in pan for about 15 minutes before turning out on a wire rack to cool completely before slicing and serving.
Bread will keep airtight at room temperature for up to 1 week, or in the freezer for up to 6 months.