Preheat the oven to 350 degrees. Lightly grease a 9x5x3" loaf pan. Set aside.
2Using an electric mixer, beat together the sour cream, sugar, eggs and vanilla on low speed for a couple of minutes until well blended. Stop the mixer and then add in the flour leavening agents and salt. Continue to beat on low until well combined.
3Fold in the apples and half the nuts into the batter. Transfer the batter into the greased loaf pan.
Sprinkle the rest of the nuts on top and then press them lightly into the batter. Bake for about 60 minutes or until a toothpick inserted into the center comes out clean.
4Cool in the loaf pan for about 20 - 30 minutes and then transfer to a wire rack to cool completely. So it doesn't get too dark, I suggest using a light colored loaf pan.
5FOR THE PRALINE SAUCE:
In a small sauce pan, place the butter and brown sugar. Using medium heat, bring to a boil. Lower the heat and then simmer lightly for about one minute, stirring constantly until the sauce thickens. Remove from heat and then drizzle over the bread. Cool completely.