In a large bowl, dissolve yeast in warm water. Stir in brown sugar and salt. Add cake flour; stir well. Add enough all-purpose flour to form a soft dough.
Turn onto a floured surface; knead until smooth and elastic, about 6-8 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until dough has risen slightly, about 30 minutes. Punch dough down; divide into 14 balls. Roll each ball into a 15-in. rope.
In a bowl, dissolve baking soda in hot water. Dip each rope in baking soda mixture; drain on paper towels. Form into pretzel shapes and place on greased baking sheets. Bake for 15 minutes or until golden brown.
Combine sugar and cinnamon in a small bowl. Brush pretzels with butter, then dip in cinnamon-sugar. Serve warm.