Preheat the oven to 325 degrees F.

Line 6 muffin cups with cupcake liners (I used parchment liners) and spray with cooking spray

Crack eggs in a medium bowl and add milk, whisking to combine

Drain the thawed spinach well, pressing out any excess water

Add the spinach, scallions, turmeric and salt to the eggs and whisk together

Add feta and stir until just combined

Divide the mixture among the 6 cups

Bake frittatas for about 30 minutes, until just firm at the top, with no raw egg appearance.

Remove from the oven and cool for a few minutes before serving.

Serve warm, or allow the frittatas to cool to room temperature before covering and storing in the refrigerator