Preheat the oven to 350°F. Line the bottom of a 12-inch springform pan with parchment paper and butter the sides of the pan.

For the top of the cake, peel, halve, and core 4-5 of the apples, and cut each half into 6 even slices. Toss the apple slices with half of the lemon juice and set aside.  Peel, halve, and core the remaining apples, and then cut them into 1/3-inch dice. Toss with the remaining lemon juice and set aside.

Grate the almond paste and place it in the bowl of a stand mixer fitted with the flat beater attachment. Add the salt and melted butter; beat for 1 to 2 minutes, until smooth. Then beat in the sugar and almond extract. Beat in the yolks and whole eggs, one at a time, beating for 30 seconds after each addition. Scrape down the sides of the bowl.

In a separate bowl, whisk together the flour, cornstarch, and baking powder. Beat into the almond batter, and then fold in the diced apples. Scrape the batter into the prepared pan and smooth the top. Distribute the sliced apples decoratively in concentric rings on the top of the cake. Then, using the flat of your hand, gently push the apples into the batter; they should not be submerged, but rather lightly anchored.

Place the pan in the oven and bake for 1 hour and 10 minutes, or until the top is golden brown and a tester inserted into the middle of the cake comes out clean. Remove the pan from the oven and place on a rack to cool.

Immediately heat the apricot jam over medium-high heat until just bubbling. Brush a thin layer of the hot jam over the still-hot cake. Let cool completely before removing the springform ring. The cake will keep at room temperature, lightly wrapped in plastic wrap, for several days.