Ricotta cake

The delicate art of pastry making is one that I do not yet master! You need to be something of a chemist to fully understand the finer points... Many of them escape me, you can't leave anything to chance, the temperature of the oven, the proportion of ingredients, ...
However, I read the 'les secrets de la casserole' by Hervé THIS (by the way, this man reconciled me with physics. Now, I can make 20 liters of mayonnaise from only 1 egg yolk! Marvellous idea to teach chemistry through cookery, or vice versa...)

I tested this cake recipe and by miracle, it was a success!

Ingredients:
75 gr. of ricotta
75 gr butter
170 gr castor sugar
3 eggs, separate white from the yolks
175 gr. of flour
Peel from 1 lemon
Lemon juice
1 1/2 spoonful with brewers' yeast
Icing sugar, for decoration

Butter the cake tin sprinkle over with flour. Preheat the oven to 180°C. In a mixer, mix the softened butter with castor sugar. Then incorporate the ricotta. Beat the egg yolks together and add them to the preparation. Then add 2 spoons of flour and the lemon juice and peel. Sieve the yeast and the remainder of the flour, and mix it all together. Beat the egg whites until firm, and incorporate delicately. Pour the mixture into the cake tin, and cook for 45 min. Leave the cake to cool for 10 min before turning it out. Powder with icing sugar.