In a large bowl, combine 1-1/2 cups flour, sugar, salt and yeast. In a saucepan, heat milk and butter to 120°-130°. Add to dry ingredients; beat just until moistened. Add eggs; beat on medium for 2 minutes. Stir in enough remaining flour to form a firm dough. Turn onto a floured surface; knead until smooth and elastic, about 5-7 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 70 minutes.
In a small bowl, combine the first seven filling ingredients; beat for 2 minutes. Punch dough down; turn onto a lightly floured surface. Divide in half; roll each into a 16-in. x 8-in. rectangle. Spread filling to within 1/2 in. of edges. Sprinkle with nuts. Roll up jelly-roll style, starting with a long side.
With a sharp knife, cut each roll in half lengthwise. Open halves so cut side is up; gently twist ropes together. Transfer to two greased 9-in. round baking pans. Coil into a circle. Tuck ends under; pinch to seal. Cover and let rise in a warm place until doubled, about 45 minutes.
Bake at 350° for 25-30 minutes or until golden brown. Cool for 10 minutes; remove from pans to wire racks. Combine the confectioners' sugar, maple flavoring and enough milk to achieve desired consistency; drizzle over warm cakes. Yield: 2 coffee cakes.