Combine 1 cup flour, yeast, sugar, and garlic salt in a large mixing bowl; stir well.
Combine milk and 1/3 cup butter in a saucepan; cook over medium-low heat until mixture reaches 120° to 130°, stirring often.
Gradually add hot milk mixture to flour mixture, stirring well. Add eggs; beat at low speed with an electric mixer until blended. Beat 2 minutes at medium speed. Gradually stir in enough remaining flour to make a soft dough.
Turn dough out onto a well-floured surface, and knead until smooth and elastic (about 6 to 8 minutes). Shape into a ball. Place in a well-greased bowl, turning to grease top. Cover and let rise in a warm place (85°), free from drafts, 30 minutes or until doubled in bulk.
Meanwhile, combine 1/2 cup softened butter, herbs, and onion; stir well. Set aside.
Punch dough down; turn out onto a lightly floured surface, and knead lightly 4 or 5 times. Divide dough in half. Roll half of dough to 1/4" thickness; cut with a 4" round cutter.
Spread 2 teaspoons herb butter on tops of dough rounds; fold in half, bringing bottom within 1/4" of top half, allowing herb butter to peak through top. Place half-moons upright next to each other on a greased baking sheet.
Repeat procedure with remaining dough and herb butter, making a second loaf. Cover and let rise in a warm place, free from drafts, 20 minutes or until doubled in bulk.
Bake at 375° for 14 minutes or until lightly browned. Brush loaves with remaining herb butter. Garnish, if desired.