Preheat oven to 400° Fahrenheit. Adjust oven racks as needed so one rack is positioned in middle of oven.
With sharp knife, cut kale leaves away from stem. Discard stem. Loosely stack or roll kale leaves, then roughly chop kale into medium-to-large pieces.
Transfer chopped kale to salad spinner. Rinse kale thoroughly under running water. Drain well, then spin kale in salad spinner until completely dry. If necessary, spread kale leaves out on paper towels and pat dry.
Transfer kale to large mixing bowl. Add olive oil, garlic, salt, and pepper. Toss ingredients until kale is completely coated with oil and spices.
Transfer kale onto baking sheet and spread pieces out into one even layer. Divide kale between 2 baking sheets as needed depending on size of pans and amount of kale.
Place baking sheet on middle rack in preheated oven. Cook 5 minutes, then remove baking sheet from oven and carefully stir kale with tongs or wooden spoon. Return baking sheet to oven and cook another 3 to 5 minutes or until kale is wilted with crisp edges.
When kale is crispy, remove baking sheet from oven. Transfer kale to serving bowl or plate and serve immediately.