Heat the oven to 350°F and prepare a 9x5-inch loaf pan with parchment paper or grease it well. Make sure the parchment reaches over the long sides if you want an easy lift after baking.

Peel the two medium zucchini and boil them until very tender, about 15 min, then drain thoroughly. The zucchini should mash easily with no firm pieces remaining.

Mash the drained zucchini with a fork or process it into a smooth pulp, then blot away any water pooling on the surface if desired. The finished pulp should look thick and moist rather than watery.

Beat the butter and monk fruit sweetener together in a separate bowl until evenly combined. The mixture should look creamy and lighter in texture than unmixed butter.

Mix in the eggs and banana extract until the batter base looks smooth. The banana aroma should become noticeable as the extract blends through the butter mixture.

Blend in the zucchini pulp, olive oil, and ricotta cheese until fully incorporated. Stop when the mixture looks creamy and uniform, without visible ricotta lumps.

Add the almond flour, cinnamon, baking powder, xanthan gum, salt, and optional walnuts, then mix until no dry patches remain. The batter will become thicker as the almond flour absorbs the wet ingredients.

Transfer the batter to the prepared pan and bake for 50 to 55 min. The loaf is ready when the perimeter is golden, the top has a slight crack, and the center feels set rather than loose.