Spinach Pesto Spaghetti with Asparagus

Name: Spinach Pesto Spaghetti with Asparagus
Cuisine: European, Italian, Mediterranean
Ingredients: 2 cups fresh basil; 3 cups baby spinach; 1 clove garlic; 1/4 cup fresh grated Parmesan cheese (optional); 2 Tbsp raw pepitas (aka. pumpkin seeds); 1/4 cup extra virgin olive oil (plus more if needed for desired consistency); 1 tsp salt (plus more for pasta water); 1/2 tsp ground pepper; 1/2 tsp lemon juice (this brightens the sauce and preserves the bright green color); 1 lb. spaghetti (or noodles of choice); 1 bundle asparagus (tough ends removed and sliced into fourths)