A light, fluffy summery cake that you can make any time of year.
In a large bowl, thoroughly blend flour, baking powder, sugar, salt and poppy seeds. Make a well in the center and add oil, egg yolks, milk, vanilla, lemon rind and lemon juice. Mix thoroughly with a spoon until smooth.
In a stand mixer or with a hand mixer, add cream of tartar to egg whites and beat until whites form very stiff peaks. Gently fold whites into yolk mixture with a rubber spatula.
Pour into well-greased and floured bundt pan (The Kitchn's classic method is my go-to magic). Bake in low oven, 325 deg F for 45 to 50 minutes (or until done). Let stand for at least 15 to 20 minutes before removing from pan. If the cake hasn't pulled away from the edges, use a butter knife to loosen the edges and middle before turning upside down.
Stir sugar and water in a saucepan over medium heat. Make sure to keep stirring until the sugar has dissolved, and then remove from heat.
Place the slightly-cooled bundt cake on a wire rake over a large plate or serving dish -- or anything you don't mind using to catch the excess syrup as it drips off the cake. Spoon the syrup on top of the cake -- and don't hesitate to make a second pass with the syrup that's dripped off onto your dish. Allow cake to cool before frosting.