Preheat oven to 425 degrees.
Spray two or three six-cavity donut pans with cooking spray.
Set aside.
In a large mixing bowl, whisk flour, baking powder, baking soda, salt and sugar.
Set aside.
In a medium sized mixing bowl, whisk the milk, sour cream and eggs until smooth.
Whisk in melted butter, canola oil, lemon juice, lemon peel and poppy seeds.
Pour the butter mixture into the flour mixture and stir just until combined.
Do not overmix.
Batter will be very thick.
Spoon batter into a large zip-lock bag.
Trim a corner off the bottom of the bag and pipe batter into each donut cavity.
Fill each cup 3∕4 full.
Bake for 10 minutes at 425 degrees or until the edges are lightly browned.
Remove from oven and cool approximately 2 minutes on a cooling rack.
Remove donuts from the pan and dip in lemon glaze.
Place donuts on cooling rack and immediately sprinkle donuts with freshly grated lemon zest before glazing the next donut.
Set out on wire racks until icing sets, approximately 10 minutes.
Serve.