Heat butter and milk over low on the stovetop until butter has melted. Cool to lukewarm. 

In a large bowl, dissolve the yeast in the warm water and beat in the egg yolk. Blend in the cooled milk mixture.

Sift in the flour, salt, and sugar. Beat until the mixture is smooth and creamy.

Cover bowl and refrigerate overnight.

The next day, blend walnuts, raisins, milk and apple butter in a saucepan over medium-low heat. Stir until mixture thickens. Let cool.

Beat egg whites until stiff and slowly add in the 1 cup of sugar. Fold into the cooled apple butter walnut mixture.

Spray bread pan with non-stick cooking spray.

Divide dough into two equal pieces (4 if using 2 small bread pans) and dust each with flour. Roll out (one at a time) to make a large circle. Pour half of the walnut filling onto the dough and spread out over the dough and roll up jelly-roll fashion. Set aside and roll our second piece of dough and repeat process. When done, twist the two pieces of filled dough together, making a braid or twist. Place in carefully in bread pan.

Place on stovetop and let rise for 30 minutes while preheating the oven to 350 degrees.

Bake for 40-45 minutes.

Cool in pan for 15 minutes and then invert to a cake plate. Drizzle with a vanilla glaze.

Serve fresh for best results or reheat slices in microwave for 30 seconds prior to serving to retain moistness.