Melt the butter in a large skillet with a lid over medium heat.
Add the minced garlic and cook for 30 to 60 seconds, stirring frequently, just until fragrant.
Pour in the heavy cream and broth, stir well, and bring the mixture to a gentle simmer.
Stir in the potato gnocchi and drained sun-dried tomatoes, spreading the gnocchi into an even layer.
Cover the skillet and cook for 4 minutes without stirring.
Remove the lid, stir well, and test one gnocchi for tenderness.
Continue cooking uncovered for 2 to 4 minutes, stirring frequently, until the gnocchi is tender and the sauce lightly coats the back of a spoon.
Reduce the heat to low, then stir in the spinach, Parmesan, and lemon juice until the spinach wilts and the cheese melts smoothly.
Season with kosher salt, black pepper, and additional lemon juice to taste.
Remove the skillet from the heat and garnish with fresh basil, additional Parmesan, black pepper, or crushed red pepper before serving.