Combine the heavy cream, lemon juice, orange juice, lemon zest, and 3 oz/90 g of the sugar in a saucepan and heat, stirring to dissolve the sugar, until the mixture reaches 180°F/82°C.
Blend the eggs and egg yolks with the remaining 1 oz/30 g sugar to make the liaison. Temper by gradually adding about one-third of the hot cream, whisking constantly. Add the rem