Preheat your oven to 375°F (190°C). In a mixing bowl, prepare the cornbread muffin mix according to package instructions, combining it with water or milk. Spoon batter into a greased mini muffin tin, filling each cup about two-thirds full. Bake for 11-13 minutes until golden brown.

Remove muffins from oven and cool them in the tin for 5 minutes. Transfer to a wire rack to cool completely. If crumbly, freeze for 15 minutes before slicing.

Assemble by slicing the muffins in half. On each bottom half, layer a slice of deli ham, a square of Swiss cheese, and a smear of yellow mustard.

Place the top half of each muffin back on and secure with a toothpick.

Arrange on a platter for guests to enjoy either warm or at room temperature. Pair with spicy mustard or a dipping sauce if desired.