Preheat Blackstone griddle to medium heat. Drizzle vegetable oil then add mushrooms, brussels, and bacon. Lightly season the mushrooms and brussels with salt and pepper. Cook for 15 minutes until bacon is crispy and cooked through.
Add pierogis to the griddle. Use a squirt bottle of water to steam the pierogis until heated through. Cook on both sides until toasted.
Mix the pierogis with the bacon, brussels, and mushrooms. Pour honey mustard over the top, then mix for 2 minutes. Remove from the griddle, serve immediately.
