Sift the flours and the baking powder together. In a bowl, mix the egg yolks and milks together, add the sifted flour mixture, onion, lemon zest, chives, parsley, salt and pepper. Mix gently with a rubber spatula until the consistency of pancake batter, you may need to add a little more whole milk. Fold in the egg whites. On a hot griddle, melt a little butter. Ladle 3 to 4 ounces of the batter into the melted butter and flip when golden brown. Continue cooking until cooked all the way through.
Assembly: Place the warm blini on the serving plate. Spread the dill cream over the blini. Lay a piece of sliced salmon across the top of the blini, covering it entirely. Place a little more dill cream in the center of the salmon. Place the caviar on top of the dill cream. Sprinkle the chives and red onion on the salmon, for garnish.