Add the baby spinach, raw almonds, garlic cloves, fresh lemon juice, and salt to a food processor. Pulse until roughly combined, then slowly drizzle in the extra virgin olive oil while the processor runs, creating a chunky pesto texture. Stir in the grated parmesan cheese by hand to preserve its texture. Set aside until ready to toss with pasta—the pesto can be made up to a few hours ahead and stored in the refrigerator.

Pat the sliced chicken breasts dry with paper towels, then season both sides generously with salt, black pepper, Italian seasoning, and red pepper flakes. Heat 1 tablespoon of olive oil in a large skillet over medium-high heat until shimmering. Working in batches if needed to avoid crowding the pan, sear the chicken strips for 5-6 minutes per side until golden brown and cooked through (internal temperature should reach 165°F). I like to let the chicken develop a nice golden crust before flipping—this takes about 5 minutes, so resist the urge to move it around too much. Transfer to a clean plate when done.

While the chicken cooks, bring a large pot of salted water to a rolling boil. Add the penne pasta and cook for 10 minutes or until al dente (tender but still slightly firm to the bite). Before draining, scoop out and reserve 1 cup of the starchy pasta water—this liquid is essential for adjusting the consistency of the pesto when tossing. Drain the pasta in a colander but don't rinse it, as the residual starch helps the pesto coat the noodles.

Return the cooked pasta to the large pot (off heat) and add the spinach pesto from Step 1, stirring gently to coat every strand. Add pasta water from Step 3 a few tablespoons at a time, tossing until the pesto reaches your desired consistency—you want it creamy and clinging to the pasta, not dry or too thick. Top with the seared chicken from Step 2 and gently fold it in, being careful not to break the strips. For a lighter dish, I prefer to arrange the chicken on top rather than fully mixing it in, which keeps it visually appealing and prevents it from breaking apart.

Divide the pasta among serving bowls or plates, ensuring each portion has chicken and pesto evenly distributed. Garnish with fresh chopped parsley and serve immediately with fresh lemon wedges on the side for brightness and acidity.