1/4 cup fat-free mayonnaise
1/4 teaspoon grated lime zest
2 tablespoons lime juice
1 teaspoon minced fresh thyme or 1/4 teaspoon dried thyme
1/2 teaspoon pepper, divided
1/4 cup all-purpose flour
2 large egg whites, lightly beaten
3/4 cup cornmeal
1/4 teaspoon salt
2 medium green tomatoes
2 medium red tomatoes
8 slices Canadian bacon, warmed
Preheat air fryer to 375°. Mix mayonnaise, lime zest and juice, thyme and 1/4 teaspoon pepper; refrigerate until serving. Place flour in a shallow bowl; place egg whites in a separate shallow bowl. In a third bowl, mix cornmeal, salt and remaining 1/4 teaspoon pepper.
Cut each tomato crosswise into 4 slices. Lightly coat each slice in flour; shake off excess. Dip in egg whites, then in cornmeal mixture.
In batches, place tomatoes on greased tray in air-fryer basket; spritz with cooking spray. Cook until golden brown, 4-6 minutes. Turn; spritz with cooking spray. Cook until golden brown, 4-6 minutes longer.
For each serving, stack 1 slice each green tomato, bacon and red tomato. Serve with sauce.