Preheat oven to 350 degrees F. Line 4 muffin cups with paper liners.

In a medium mixing bowl, stir together flour, sugar and salt. Add melted butter to flour mixture and stir until moistened.

Combine buttermilk and baking soda in a small bowl and stir well. Stir in egg yolk and vanilla paste. Stir buttermilk mixture into flour mixture and beat heartily for 1 minute or two. Again, we just did this with a wooden spoon - but we beat it a lot! A mixer on medium speed would have been better. Beat until light and fluffy.

Divide evenly among the 4 muffin cups. Bake for 20 minutes.