Easy Beef Sliders with Melty Cheese (Ready in 40 Minutes)

Ingredients

• 1 tablespoon neutral oil
• 1 small yellow onion, finely diced
• 1 1/2 lb (680 g) 85 percent lean ground beef
• 2 tablespoons yellow mustard
• 1 tablespoon Worcestershire sauce
• 1 teaspoon garlic powder
• 1/2 teaspoon smoked paprika
• 1 teaspoon kosher salt
• 1/2 teaspoon black pepper
• 12 connected slider rolls or Hawaiian-style sweet rolls
• 8 oz (225 g) sliced or shredded cheddar cheese
• 1/2 cup sliced dill pickles, patted dry
• 3 tablespoons unsalted butter, melted
• 1 teaspoon yellow mustard
• 1 tablespoon sesame seeds
• 1/3 cup mayonnaise
• 2 tablespoons ketchup
• 1 tablespoon yellow mustard
• 1 tablespoon sweet pickle relish
• Pinch of black pepper