Mix all the dry ingredients in a bowl and whisk to blend well.

Add the wet ingredients, all except the jam and food coloring, to another bowl and mix well.

Combine the wet ingredients with the dry ingredients and stir until just combined.

Scoop out about 1/2 cup of batter into a small bowl and add in the raspberry jam and optional food coloring. Mix until well combined.

Add the half the vanilla batter to the buttered or oiled loaf pan. Then drop the raspberry batter on top of the vanilla batter with a spoon. Make about 4 dollops of raspberry batter.

Add the rest of the vanilla batter on top and dollop the rest of the raspberry batter on top.

Now with a knife make a few passes horizontally and vertically to swirl in the raspberry batter to the vanilla batter. I did about three passes each way but I think a few more would have worked out better. Mine did not swirl as well as it should have so make a few extra passes.

Bake in a 375 degree preheated oven 40 minutes or until golden and baked through.

Let the loaf cool about 5 minutes in the pan, then remove from the pan and let cool on a wire rack.