Preheat oven to 350 degrees F. Butter and flour inside of a bundt pan.

In a large bowl, rub the lemon zest and lilac blossoms into the sugars with your fingertips. Whisk in the oil until smooth.

Add the eggs 1 at a time, and whisk until combined. Scrape down the bowl.

Combine the flour, baking powder, baking soda, and salt in a second bowl. In a liquid measuring cup, combine 2 tablespoons of lemon juice and yogurt.

Add the flour and yogurt mixtures, alternating between them, to the oil-and-sugar mixture.

Spread the batter in the pan, smooth the top, and rap the pan on the counter to ensure there are no air bubbles trapped in batter. Bake for 45 minutes to 1 hour, until a toothpick inserted in center comes out cleanly. Let cool for 10 minutes in the pan and then invert it onto a rack.

Add syrup, glaze, and candied lilacs to finish cake (recipes below).

Combine 2 tablespoons of sugar with the juice of 1 fresh lemon in a small saucepan and cook over low heat until sugar dissolves. Poke holes in cake with a skewer or toothpick, then spoon the lemon syrup over the cake. Let cake cool completely while it absorbs the syrup.

Make the glaze: Combine the confectioners sugar, juice of second lemon, and salt in a bowl, whisking until smooth. Drizzle glaze over the top of cooled cake, allowing glaze to drip down the sides.

Brush lilac blossoms with egg white and sprinkle heavily with sugar. Let flowers dry out for ½ an hour, then top the cake with the lilacs.