Preheat oven to 350°. Spray a 24-count mini muffin pan with nonstick cooking spray.
On a lightly floured surface, unroll each pie crust. Using a 2 3/4-inch round cutter, cut 12 circles from each pastry. Press pastry into the bottom and up sides of each muffin cup.
In a medium bowl, combine spinach, cheese, bell pepper, and green onion. Divide spinach mixture evenly among prepared muffin cups.
In a medium bowl, whisk together half-and-half, eggs, Dijon mustard, garlic powder, seasoned salt, and pepper. Divide egg mixture evenly among muffin cups. Bake for 15 to 20 minutes, or until set. Let cool in pan for 2 minutes. Remove from pan and serve warm. Garnish with red pepper and chopped fresh thyme, if desired.
