01 - Preheat your oven to 350°F (180°C). Prepare a baking sheet by lining it with parchment paper.
02 - In a small mixing bowl, combine Dijon mustard, whole-grain mustard, honey, lemon juice, a pinch of salt, and a dash of black pepper. Whisk thoroughly until the sauce is well blended.
03 - Carefully slice each mini slider bun horizontally. Arrange the bottom halves of the buns on the prepared baking sheet.
04 - On each bottom bun, layer a slice of thinly sliced halal corned beef. If using, place a slice of halal Swiss cheese directly over the corned beef.
05 - Place two dill pickle slices onto each slider. Spoon a small amount of the prepared mustard sauce evenly over the meat and pickles.
06 - Position the top halves of the slider buns over the fillings. Using a pastry brush, lightly coat the tops of all the buns with the melted unsalted butter.
07 - Transfer the baking sheet to the preheated oven. Bake for 7 to 10 minutes, or until the buns are lightly toasted and golden brown, and the cheese is fully melted and bubbly.
08 - Remove the sliders from the oven. For an optional decorative touch, sprinkle with finely chopped fresh parsley. Serve immediately while warm, with any remaining mustard sauce on the side for dipping.