Tyrolean PIE with custard

Tyrolean PIE with custard (diameter 23 cm, weight 1800 g)
Sponge cake:
2 eggs
70 gr. sugar
50 gr wheat flour
20 gr. starch
zest 1/2 lemon
Custard:
300 ml milk
1 egg
90 gr. sugar
1 tsp vanilla sugar or vanilla
20 gr. corn starch
8 gr. gelatin (I have dr.oetker) + 2 tbsp. milk
150 gr. cream 33 - 35%
Syrup:
150 ml. hot water
30 gr sugar
1.5 tbsp lemon juice
Strawberry Jelly:
500 gr. strawberries
2 strawberry jellies (per 200 ml of water each pack)
Bake a biscuit at 338 F - 25 minutes. Baking time and temperature depend on the characteristics of the oven.