Toast walnuts in a dry skillet over medium heat for 3-4 minutes until fragrant, then chop and add at the very end to maintain their crispy texture instead of softening them in the warm pasta.

Save 1 cup of starchy pasta cooking water before draining—use it to emulsify the butter and lemon juice into a silky sauce that clings beautifully to the spaghetti.

Always zest your lemons first while they're whole and firm, then juice them afterward; zesting a halved lemon is messy and less efficient.

Combine butter, lemon juice, and zest in the warm pasta pot off the heat, then toss with drained spaghetti and pasta water to prevent the butter from breaking and create a cohesive emulsion.

Drizzle premium extra virgin olive oil over the finished dish just before serving to add fruity notes and depth that elevate the simple flavors without the heat destroying its delicate qualities.