To make the meatballs:
Heat 2 tablespoons of olive oil in a medium-sized skillet. Add leeks and cook until brown (10 minutes). Set aside and let cool. In a large bowl, combine ground turkey, leeks, eggs, chopped sage, garlic, 1 teaspoon salt and 1/2 teaspoon pepper.
Using a strong spatula or your hands (I like using my hands), mix well. Shape the mixture into 1-inch balls
To bake the meatballs:
Preheat oven to 400 degrees. Line a rimmed baking sheet with foil for easy cleanup.
Coat a wire rack with nonstick spray and set on prepared baking sheet.
Arrange meatballs on rack, brush with oil and bake until browned with crispy edges, about 15 to 20 minutes (an internal thermometer should read 155 degrees for 15 seconds).
To freeze the meatballs:
Arrange in a single layer on a baking sheet, spacing them so they do not touch.
Freeze until solid, about 1 hour, then transfer to a freezer-safe container and store up to 1 month.