Toast the marcona almonds.

Mince the toasted almonds in a food processor.

Add parsley, olive oil, Parmesan, and salt to the food processor.

Puree to combine the pesto ingredients.

Reserve the pesto in the refrigerator.

Halve the leeks lengthwise and cut crosswise into 1/2-inch pieces.

Rinse the sliced leeks well under cool water.

Drain the leeks.

Coat a 10-inch skillet with 2 tablespoons of olive oil and place over medium heat.

Add the leeks, garlic, and thyme to the skillet.

Cook, stirring occasionally, until the leeks are tender but not brown, about 10 minutes.

Season with salt and pepper.

Transfer the leek mixture to a 9-by-13-inch baking dish coated with non-stick cooking spray.

Spread the leeks out in an even layer.

Add the remaining 1 tablespoon of oil to the same skillet and return to medium heat.

Add the zucchini and saute for 5 minutes, until tender.

Season with salt and pepper.

Transfer the zucchini to the baking dish, and spread out on top of the leeks.

Put the eggs, ricotta, and reserved Parsley Pesto in a large bowl and whisk until blended.

Season with salt and pepper.

Gently stir with a wooden spoon to incorporate the egg mixture with the vegetables.

Preheat the oven to 300-degrees F (150-degrees C).

Put the baking dish into a larger roasting pan and pour hot water into the roasting pan to come halfway up the sides of the baking dish to create a water bath.

Bake the frittata for 50 minutes.

Gently shake the pan; if it still appears loose in the center, return to the oven for another 5 minutes.

The frittata should be set and only slightly jiggly in the center.

Remove the frittata from the water bath and let it rest at room temperature before cutting.