Prepare pasta as directed on the package.

Meanwhile, mix ricotta, 1 tablespoon of lemon zest, salt and pepper, in a small bowl.  Set aside.

Chop peppers into bite-sized pieces, mince garlic. 

Heat a large skillet over medium-high heat; add 1 tablespoon of oil and allow it to heat up.  Add peppers and garlic, cook for 1-2 minutes. Add pasta and chopped walnuts, toss to coat; add spinach and cook for 1-2 minutes so leaves begin to wilt. 

Remove from heat, gently fold in ricotta mixture; spritz with fresh lemon juice and a drizzle of remaining olive oil, if desired.

Serve with grapes.