Pour <quantity>500<unit>ml</unit></quantity> of milk into a saucepan. Add <quantity>2</quantity> lemon peels. Bring it to a boil over medium-high heat, stirring occasionally

Add <quantity>100<unit>g</unit></quantity> of sugar and <quantity>100<unit>g</unit></quantity> of egg yolks to a bowl

Add <quantity>40<unit>g</unit></quantity> of cornstarch and whisk until it is silky smooth

Slowly pour the milk over the egg mixture. Whisk it continuously until well mixed

Transfer the mixture to the saucepan and warm it over medium heat. Stir constantly until the mixture is thick like a custard

Strain the pastry cream through a sieve into a bowl

Add <quantity>20<unit>g</unit></quantity> of butter and mix until it melts

Press cling film directly on top of the cream to prevent a skin from forming

Place the bowl in the refrigerator until it is cool. Remove the cling film and whisk. The pastry cream is ready

Grind <quantity>70<unit>g</unit></quantity> of toasted almonds to a coarse flour in a food processor

Add <quantity>120<unit>g</unit></quantity> softened butter and <quantity>120<unit>g</unit></quantity> white sugar to a stand mixer bowl. Beat with a paddle attachment on high speed for 5m until the butter becomes pale, light, and smooth

Add the almond flour to the bowl

Add <quantity>20<unit>g</unit></quantity> cornstarch. Scrape down the sides of the bowl with a rubber spatula and mix on low speed until incorporated

Add <quantity>1</quantity> egg and <quantity>1</quantity> egg yolk while mixing. Mix until incorporated

Add <quantity>180<unit>g</unit></quantity> of the Pastry Cream. Mix on high speed until fully incorporated

Transfer to another bowl. The frangipane is ready