reformulating a cake recipe to make it flourless

i have a walnut cake that i want to make flourless. it has 1 cup of AP and only 1 egg. i think if i use 2 eggs separated, whipping the whites will allow me to inflate the cake w/o AP. too many eggs can make a cake heavy. i may also add a 3rd egg white but not the yolk. i welcome any thoughts.

the lemon almond paste cake i cited had 3/4 cup AP. it also had 4 eggs. by incorporating the 4 yolks separately and then whipping the 4 whites, it rose and the cake was a huge hit w/o the flour. i have orders for it for passover by people who tasted the dry run.

one of the 2 people buying the cake for passover has celiac disease and will stay flourless. i'm now looking at a walnut cake w 1 cup of flour. it has only 1 egg. i don't really know what eggs do tho i think they bind the cake. are too many eggs in a cake bad for the outcome or are they simply wasteful? i'm thinking 1 more egg won't make a big difference. instead of introducing the 1 egg, i would add the 2 yolks separately and whip the 2 egg whites separately. worth a try and happy to detail the experiment.

i made the almond paste lemon olive oil cake w/o flour even tho i had a recipe that included flour. it did work. instead of adding the 4 eggs one at a time, i separated 4 eggs. i put only the yolks in when it asked for eggs. i kept the whites separate and whipped them to hard peaks, then added them.

Try a recipe with almond flour, like this one: https://www.simplyrecipes.com/recipes/flourless_lemon_almond_cake/

Here is a copycat recipe for Ikea's almond cake: https://www.thecookingfoodie.com/recipe/Swedish-Almond-Cake-Recipe--Ikea-Almond-Cake

I believe both of these are called mandeltorta or mandeltårta. No need to reinvent the wheel. Good luck!

Alan - a few thoughts.
1) Chocolate Lava Cake aka Molten Chocolate Cake, from Chef Jean-Georges Vongerichten. Has 2 tbsp flour which I'm guessing you could omit or replace with matzo meal. Has a very 80s or 90s vibe, famous for a reason and still delicious.
https://www.foodandwine.com/recipes/molten-chocolate-cakes
2) When making something new to me, I start with someone else's tried-and-true template, then deviate or make up variations. Here's one from King Arthur Flour.
https://www.kingarthurbaking.com/recipes/flourless-chocolate-cake-recipe
3) Another dessert good for Passover is chocolate mousse, and I have recipes made with avocado or olive oil instead of the whipping cream, so servable at any kosher table (meat, dairy, neutral).
Learned the avocado version from Foodies.ca (a television series in early 2000s) but can't find it's recipe online. Another version is here
https://www.splendidtable.org/recipes/chocolate-avocado-mousse-martinis-with-fresh-raspberries
and the olive oil one, recipes from Lucy Waverman (cooking teacher, cookbook author in Toronto) and Joan Nathan (cookbook author & columnist, Washington)
Negevnectars.com/joan-nathan%E2%80%99s-mousse-au-chocolat-et-a-l%E2%80%99huile-d%E2%80%99olive/
and wine writer at Globe and Mail (Toronto) Beppi Crosariol recommends late-harvest Canadian dessert wine or from France a Muscat de Beaumes-de-Venise.
Ice wine (from Canada or Germany) would likely go well with all these chocolate confections.
Good luck in your experimenting and eating.