Prepare the fresh basil pesto.

Combine walnuts, garlic, basil leaves, salt, and pepper in a food processor and pulse until coarsely chopped.

With the processor running, slowly drizzle olive oil into the mixture until a smooth pesto forms.

Add Parmesan cheese and pulse for another minute.

In a mixing bowl, combine chicken breast with basil pesto, fresh cream, and lemon juice.

Marinate for at least 1 hour.

Heat a grill pan or skillet over medium heat.

Add garlic butter to the pan.

Place the marinated chicken breast on the hot pan.

Cook for 8-10 minutes per side, or until fully cooked and juices run clear.

Transfer the grilled chicken to a serving plate and serve hot.