Preheat the oven in advance to 180 °C, top-bottom mode (about an hour).

Line the baking sheet with parchment paper or a siliconized mat. I have two mats—one siliconized mat with markings for eclairs, and the other is a perforated mat with markings for eclairs too. This is very convenient for piping the cookies.

Carefully separate whites from yolks.

Beat whites with salt to beer foam (this means you don't see the yellow egg white at the bottom; the entire consistency is white).

Gradually add 75 g sugar to the whites in several additions.

Beat to dense stable peaks (turn the bowl upside down and the white stays in place, doesn't move anywhere).

Beat yolks with remaining 75 g sugar and vanilla. The mass should become light and thick (beat for 3–4 min).

Gently fold in 1/3 of the whites into the yolk mass.

Sift flour with cornstarch, gently fold into the egg mass.

Add remaining whites, mix with a spatula from bottom up. The dough is airy, not liquid.

Transfer the dough to a pastry bag and pipe sticks 8–9 cm long, generously sprinkle with powdered sugar (can do twice).

Important nuance: It's best not to leave the finished dough for long, otherwise the dough will settle, as happened to me. If possible, bake all the cookies at once—bake immediately. If the dough has settled, it's okay, it doesn't affect the taste, only the rise of your cookies.

Bake for 12–15 minutes until light golden color; outside the sticks are dry, inside soft (can check with a toothpick if in doubt).

Cool completely.

In a bowl, mix mascarpone, boiled condensed milk, vanilla, and salt; mix with a mixer using the paddle attachment on minimal speed or fold with a regular spatula until combined.

Beat very cold cream to soft peaks.

Fold the cream in 2 additions into the cheese mass, gently. The cream should turn out thick, stable, and hold its shape perfectly.

Transfer the cream to a pastry bag and refrigerate until use. I divided the cream into three portions and placed them into three pastry bags.

In a saucepan, mix cream, milk, boiled condensed milk or Lotus Biscoff paste, and salt. I used Lotus Biscoff paste—it gives an interesting flavor combination.

Heat to a warm state, about 35-40 degrees (do not boil!).

Cool to room temperature.

First layer:

Quickly dip savoiardi (1/2–1 sec!) in the soak and lay in a dense layer. Spread the first half of the cream and level it.

Second layer:

Lay the second layer of savoiardi and quickly (1/2–1 sec!) dip in the soak and lay in a dense layer. Spread the second half of the cream and level it.

Third layer:

Lay the third layer of savoiardi and quickly (1/2–1 sec!) dip in the soak and lay in a dense layer. Spread the remaining cream and level it.

Refrigerate for 8–10 hours, better overnight. Top can be sprinkled with grated white chocolate (30-40 g.). Important nuances: 1.Do not soak savoiardi. 2.Salt enhances the caramel flavor. 3.The dessert is even tastier the next day.