Take 1/4 cup warm water, a pinch of sugar and yeast package, combine in a small bowl and allow to stand until foamy. In a large bowl place sugar and pour in room temperature/warm milk. Mix with wire whip until sugar is dissolved. Add two cups of cake flour and mix well. Add salt, baking powder and canola oil and mix well. Add yeast mixture and mix well. Slowly add the remaining 4 cups of all-purpose flour. Combine well, but do not knead excessively to avoid gluten formation. Allow to rise in a warm place until doubled in size. (~2 1/2 hours in a closed microwave with a jar of boiling water.) Punch down, cut into 24 pieces and form dough balls. Allow dough balls to rest for about 15 minutes. Roll out each dough ball to a disk 4 in diameter. (Make them look like a sunny side up egg. The lump of dough left in the center compensates for all the dough gathered on the bottom when closing the disk around the meat.) Place 1 heaping tablespoon of filler into center of disk, pinch closed and twist. Set filled dough ball on 2 square of waxed or parchment paper, twist side down. Place bao in large bamboo steamer. (Mine takes 6 per layer, 2 layer steamer.) Place in a warm, moist place to rise for about 30 minutes. (Again, I do this in a closed microwave with freshly boiled water in a jar.) Place the covered bamboo steamer over a wok with about 1 of boiling water. The water should be about 2 from the bottom of the steamer. Steam for 15 minutes, then remove from heat. (I do not remove the bao from the steamer immediately. I wait for about 1/2 hour to allow the bao to cool and set before exposing them to room temperature. This reduces the thermal shock and seem to prevent the formation of divots on the surface of the dough.) Stamp top center gently with rubber stamp and red food coloring. Serve hot or freeze to retain freshness. Frozen bao may be reheated by wrapping with a paper towel and microwaving for 1 minute.