1. Preheat oven to 350°F Spray a 9x5-inch loaf pan with cooking spray.
2. In a medium bowl, whisk together the flour, baking soda and salt.
3. Cut raspberries in half, then toss them with 1 tbsp flour.
4. In a separate large bowl, beat the sugar and butter with an electric mixer at medium speed until well blended (about 1 minute). Add the eggs one at a time, beating well after each addition. Add the banana, yogurt, and vanilla; beat until blended. Stir in the flour mixture; just until moist. Don't over-mix. Stir in the chocolate chunks and then gently stir in the raspberries.
4. Spoon the batter into the prepared pan. Bake for 60 minutes or until a wooden pick inserted in center comes out clean. Cool 15 minutes in the pan on a wire rack. Remove from pan and cool completely on the wire rack.
tip: I found that 60 minutes still left the middle too gooey, you may want to bake as long as 70-75 minutes. If the top is browning too much during this process, cover with foil as it is baking.