Creole Deviled Eggs

Melt butter in a medium skillet over medium. Add onion, celery, bell pepper, and 1/4 teaspoon of the salt; cook, stirring occasionally, until vegetables are softened, about 5 minutes. Remove from heat; let cool 10 minutes. Transfer 2 tablespoons of the vegetable mixture to a small bowl, and reserve for garnish. Transfer remaining vegetable mixture to a separate small bowl, and reserve for yolk mixture.

Fill a large pot with water, and bring to a boil over high. Carefully lower eggs into boiling water; cook, undisturbed, for 11 minutes, 30 seconds.

Meanwhile, fill a large bowl halfway with ice, and add enough water to cover ice; set ice bath aside.

Using a spider or slotted spoon, immediately transfer cooked eggs from boiling water to ice bath. Let stand until completely cooled, at least 5 minutes or up to 30 minutes. 

Working with 1 egg at a time, firmly tap eggs on countertop or a flat work surface until cracks form all over the shell. Peel eggs under cold water.

Cut eggs in half lengthwise, and carefully remove yolks. Using a fork, mash together yolks, mayonnaise, and mustard in a medium bowl until smooth. Stir in reserved vegetable mixture, black pepper, and remaining 1/4 tsp. salt.

Spoon yolk mixture evenly (about 1 Tbsp. each) into egg whites. Top evenly with a pinch of cayenne pepper and remaining 2 Tbsp. vegetable mixture. Serve immediately, or store in an airtight container in refrigerator up to 3 days.