In a bowl, beat the eggs with the sugar and vanilla bean pulp. Once the ingredients are incorporated, add the almond flour, baking soda, baking powder, and salt. Mix well. Divide the batter into 8 muffin cups. Bake at 180°C (350°F) for 20-25 minutes. Test with a toothpick and remove from the oven. While the cupcakes are baking, prepare the cream. Pour the milk into a small saucepan and add the lemon zest and vanilla bean. Bring to a boil. Beat the egg yolks with the sugar in a bowl. Add the cornstarch and fold it into the cream. Pour some of the hot milk into the mixture, stirring constantly. Remove the lemon zest and vanilla bean from the milk. Return everything to the saucepan over low heat and cook, stirring constantly, until the cream thickens. Transfer the mixture to a bowl and cover with plastic wrap. Remove the cupcakes from the oven and let them cool. Using a melon baller or a teaspoon, create a cavity, without touching the bottom. Set aside the remaining portion. Transfer the cream to a piping bag and fill the cavity. Seal the piping bag with the remaining portion and cover with a dollop of cream. Cut two cupcakes into chunks or coarse crumbs. Fold the pieces onto the layer of cream on the cupcakes to create a mimosa effect. Repeat with the remaining cupcakes. Decorate as desired and serve.