Step 1

Preheat: Preheat oven to 375°F (190°C).

Step 2

Cook spinach: Heat 1 (12-inch/30 cm) oven safe skillet over medium heat. Add spinach, and cook, stirring frequently, until spinach has defrosted and stated to release water, 2 to 4 minutes. Transfer spinach into a colander set in the sink. Let spinach drain as it cools.

Step 3

Cook aromatics: Return skillet to stove over medium-high heat. Heat 1 tablespoon of the olive oil. Add onion. Sauté until golden brown around the edges, 5 to 7 minutes. Add garlic, and cook, stirring constantly until fragrant, about 1 minute. Transfer mixture to a large bowl.

Step 4

Squeeze spinach and mix: Use the back of a rubber spatula or stirring spoon to press the spinach against the sides of the colander to squeeze out excess water. Add drained spinach to the onion mixture. Add kale, eggs, scallions, dill, thyme, salt, and red pepper flakes. Stir well to mix. Fold in feta.

Step 5

Layer phyllo: Give the skillet a quick wipe clean. Pour the remaining 3 tablespoons of olive oil into a small bowl. Using a pastry brush, lightly oil the sides and bottom of the pan. Place the first piece of phyllo dough horizontally across the pan. Use your fingers to gently press the phyllo into the bottom and up the sides, allowing the excess to hang over the edge of the pan. Lightly brush oil on top of the phyllo. Then, lay down the second piece of phyllo, in the opposite direction (vertically). Repeat with layers of oil and phyllo dough, alternating directions, until all 8 sheets have been used.

Step 6

Fill and bake: Spoon the spinach filling into the skillet. Then, start folding the overhanging edges of phyllo towards the center of the pan, dabbing a bit of oil in between the layers. Brush the top edges of phyllo with remaining oil. Bake until the center has firmed up and the phyllo crust is golden brown, 40 to 45 minutes. Garnish with extra feta, and serve warm with tzatziki.