Preheat the oven to 350°F. Lightly coat a 9 x 5-inch loaf pan with non-stick cooking spray and set it aside.

In the bowl of a stand mixer, cream the softened butter and sugar together until the mixture becomes light and fluffy. Add the eggs one at a time, beating until fully incorporated. Mix in the Key lime zest, vanilla extract, and Key lime juice.

In a separate small bowl, combine the flour, salt, and baking soda. Gradually add the dry mixture to the wet ingredients, mixing just until combined. Gently fold in the sour cream until the batter is smooth and fully blended.

Transfer the batter to the prepared loaf pan, spreading it evenly. Bake for approximately 50 minutes, or until the top is golden and a toothpick inserted into the center of the cake comes out clean.

Remove the cake from the oven and let it cool completely on a wire rack before glazing.

To make the glaze, whisk together the softened butter, powdered sugar, and heavy cream, adding a bit more cream if needed to reach your desired consistency.

Stir in the finely chopped raspberries, then spread the glaze evenly over the cooled cake.