Whisk the sugar and juice in a medium microwave safe bowl. Whisk in the eggs, making sure to get them completely incorporated.
Microwave for 1 minute, then whisk. Microwave for another minute, then whisk. Repeat microwaving for 30 seconds and whisking until the curd has thickened. It will get lighter in color and be like a thin pudding. Cool completely.
Place one cake layer on a cake stand or your serving plate. Spread a thin layer of lemon curd on top. Make a ring of whipped cream along on the outer edge of the cake (this helps contain the pastry cream later on). You can do this by piping the whipped cream, or making a rough ring with an offset spatula. It doesn't need to be pretty.
Pour the cooled pastry cream inside of the ring of whipped cream and spread evenly. Top with the final layer of cake, bottom side up.
Cake from Leite’s Culinaria, lemon curd from The View from Great Island, toffee from Brandini Toffee, pastry cream and whipped cream from Fork to Belly.
This cake does well in the fridge- the flavors meld, and the toffee stays crispy and crunchy.
This is a 2 layer 6.5" cake, but you can do make a 3 layer 8" cake. Double everything EXCEPT the lemon curd. If you want a 6.5" cake, you're going to have leftover lemon curd, or you can deal with measuring 1 ½ eggs to get the amount you need (and start checking the curd earlier - there's going to be less in the measuring cup, so it may cook faster than a full batch).