Serves 10 to 12 (makes 32 squares) | Active Time 20 minutes
Total Time 1 hour, plus 20 minutes cooling
1 cup (5 ounces) plus 2 tablespoons all-purpose flour
1 teaspoon baking powder
¾ teaspoon table salt
½ teaspoon pepper
¼ teaspoon cayenne pepper
1 cup chicken broth
3 large eggs
20 ounces frozen chopped spinach, thawed and squeezed dry
12 ounces Gruyère cheese, shredded (3 cups)
1 onion, chopped fine
2 garlic cloves, minced
1 ounce Parmesan cheese, grated (½ cup)
Head Start
Bake and cool squares, then refrigerate for up to 1 day. Reheat refrigerated squares, covered in foil, in 375-degree oven for 25 minutes.
Perfect Pair
Add refreshing accompaniments such as Horiatiki Salata  or Apple-Fennel Rémoulade .
WHY THIS RECIPE WORKS A simple stir-and-bake technique, loads of cheese flavor, and finger-food ease have made this spinach hors d’oeuvre a harried host or hostess’s helper for decades. Cheddar is often used in the South, where this appetizer is popular, but we prefer a combination of nutty Gruyère and Parmesan. We also exchange the milk traditionally used in the dough for savory chicken broth. Removing extra moisture from the spinach prevents our squares from turning soggy. Increasing the oven temperature, cooking the squares on the upper-middle rack, and sprinkling more Parmesan over the squares gives us a browned, crispy top. Thaw spinach in the microwave or overnight in the refrigerator. To squeeze the spinach dry, place it in a clean dish towel, gather the edges, and wring it out.

Adjust oven rack to upper-middle position and heat oven to 375 degrees. Spray 13 by 9-inch baking dish with vegetable oil spray. Whisk flour, baking powder, salt, pepper, and cayenne together in large bowl. Add broth and eggs and whisk until smooth. Stir in spinach, Gruyère, onion, and garlic until combined.
2 Transfer mixture to prepared baking dish and sprinkle with Parmesan. Bake until browned on top and bubbling around edges, 40 to 45 minutes. Let cool in pan for 20 minutes. Cut into 32 equal-size squares. Serve warm.