Bring a large pot of well-salted water to a rolling boil. Add the spaghetti and cook according to the package instructions until al dente. Before draining, remove and reserve at least 1 cup of the starchy cooking water, as it will help form the sauce.

While the pasta is cooking, place 1 tablespoon olive oil in a small skillet over medium heat. Add the thinly sliced garlic clove for the topping along with the panko breadcrumbs. Stir often until the crumbs turn a deep golden color and develop a toasted, nutty aroma, about 3 to 3 minutes 30 seconds. Transfer the mixture to a small plate and set it aside. Remove the garlic slice if it has become overly dark.

In a large skillet set over medium heat, warm the extra-virgin olive oil. Add the 4 thinly sliced garlic cloves and the crushed red pepper flakes. Cook for 30 seconds to 1 minute, stirring now and then, until the garlic is lightly golden at the edges. Keep the heat controlled so the garlic gently flavors the oil without scorching.

Add the chopped lacinato kale, sea salt, and freshly cracked black pepper to the skillet. Toss with tongs and cook for about 1 minute, just until the kale softens slightly and turns vivid green.

Transfer the drained spaghetti to the skillet. Add the capers, fresh lemon juice, lemon zest, and ½ cup of the reserved pasta water. Toss everything together over medium heat for 1 to 1 minute 30 seconds, adding more pasta water in small splashes as needed until the strands are evenly coated in a light, glossy sauce. Taste and adjust the salt only if necessary, remembering that the capers contribute saltiness.

Divide the pasta among serving bowls. Garnish each portion with chopped parsley, the crisp garlic breadcrumbs, and Parmesan or vegan Parmesan. Serve immediately while the breadcrumb topping remains crunchy.