Instant Pot Palak Paneer

Name: Instant Pot Palak Paneer
Ingredients: 2 pounds baby spinach; 4 tablespoons unsalted cultured butter (see Cook's Note); 1 pound paneer, cut into 1-inch cubes; 1 tablespoon chopped fresh ginger; 6 cloves garlic, chopped; 1 large yellow onion, finely chopped; 1 serrano pepper, chopped; Kosher salt and freshly ground black pepper; 1 teaspoon garam masala; 1 cup whole-milk Greek yogurt; 1 teaspoon finely grated lemon zest plus 1 tablespoon lemon juice; Steamed basmati rice or warmed naan, for serving