7) Add the eggs one at a time, beating well after each addition, and scraping the sides and bottom of the bowl after you've added the first 2 eggs.
8) Add the baking powder, then add the flour alternately with the milk, starting and ending with the flour. Mix until smooth. Stir in the grated lemon rind or lemon oil.
9) Spoon about 1/3 of the batter into the prepared pan, smoothing the top with a spatula. You want to add enough to cover the bottom, and start to come up the sides; but not so much that you don't have enough left over to cover the filling.
10) Distribute the stiff filling atop the batter, centering it within the ring of batter so it doesn't touch the sides of the pan. Pat it down gently.
11) Dollop the remaining batter on top, again smoothing it with a spatula.
12) Bake the cake for 50 to 55 minutes, or until a cake tester inserted into the center comes out clean.
13) While the cake is baking, make the glaze by stirring together the lemon juice and sugar. Set it aside.
14) Remove the cake from the oven, and set it on a rack. After 5 minutes, run a knife around the edge of the pan to loosen, and turn the cake out onto a rack. Place another rack on top, and flip it over, so it's right-side-up.
15) Poke the hot cake all over with a cake tester or toothpick. Stir the glaze to combine, and immediately brush it on the hot cake. Let it sink in, then brush on more glaze, continuing until all the glaze is used up.