Step #1 In a bowl, lemon peel, poppy seeds, baking powder, mix flour, & salt.
Step #2 In a small bowl, buttermilk, sugar, melted butter, whisk eggs, & vanilla to mix.
Step #3 Stir into dry ingredients until well mixed.
Step #4 Chill until firm, at least 1 hr or up to 3 hrs.
Step #5 Scrape dough onto a generously floured surface.
Step #6 With floured hands, roll dough into 1-inch balls.
Step #7 Place doughnut holes on a floured baking sheet.
Step #8 Meanwhile, fill an electric deep-fryer to the fill line or pour about 4 inches of oil into a 5- to 6-quart pan; heat to 375°.
Step #9 Using a slotted spoon to pick up one or two doughnut holes at a time, turning once, 3 to 4 mins (to check timing, carefully lower three or four holes into oil & cook, until golden brown, cut first doughnut hole to test).
Step #10 Using slotted spoon, transfer doughnut holes to paper towels to drain.
Step #11 Repeat to fry remaining holes.
Step #12 When cool enough to handle, roll each hole in glaze to coat.
Step #13 Place on a plate & let this stand until glaze is set, about 2 mins.
Step #14 Lemon glaze.
Step #15 In a bowl, mix 1/4 c lemon juice & 2 c powdered sugar until smooth.