Heat oven to 450 degrees F. Lay out jalapenos on a baking sheet and roast for 15 minutes, turning once halfway through until blistered and charred on all sides.
Let peppers cool slightly, then cut the stems off each pepper, slice in half, and scrape out seeds. Dice roasted peppers.
In a medium bowl, mash together cream cheese with roasted peppers, cheddar cheese, black pepper, and a pinch of salt. Stir together really well.
Spread this immediately on toasted bagels or store in the fridge for up to a week.