Preheat your oven to 375°F. While it heats, finely chop the onion, seed and dice the 3 jalapeños for the filling, thinly slice the 1-2 jalapeños for topping, shred the Monterey Jack and cheddar cheeses, and crack the eggs into a bowl. Having everything prepped and ready will keep your workflow smooth and prevent the egg mixture from sitting too long once combined.

In a large skillet over medium-high heat, fry the thick-cut bacon until crispy, about 8-10 minutes. Remove to a paper towel-lined plate and roughly chop once cooled. In the same skillet with about 1 tablespoon of bacon grease remaining, sauté the chopped onion over medium heat until softened and translucent, about 4-5 minutes. Let the onion cool slightly before adding to your egg mixture.

In a large mixing bowl, whisk together the eggs, softened cream cheese, and half-and-half until completely smooth with no lumps of cream cheese remaining. This gentle whisking incorporates air and creates a creamy, custard-like filling. I like to add the cream cheese in small pieces so it incorporates more evenly rather than trying to whisk one large piece.

To the custard base from Step 3, stir in the diced jalapeños, most of the shredded Monterey Jack and cheddar cheeses (reserving some cheddar for topping), the black pepper, garlic powder, salt, and the cooled sautéed onions from Step 2. Mix gently until everything is evenly distributed. The filling should have a consistent texture with the cheese and peppers distributed throughout.

Place the refrigerated pie crust in a 9-inch pie dish (or use the dish it came in if applicable). Scatter the chopped bacon from Step 2 evenly across the bottom of the crust, then carefully pour the filling mixture from Step 4 over it. Top with the reserved cheddar cheese and arrange the jalapeño slices on top in a visually appealing pattern. I find that arranging the jalapeño slices last gives the quiche a beautiful presentation and ensures they don't sink during baking.

Place the quiche on a baking sheet (to catch any drips) and bake at 375°F for 40 minutes, until the filling is set in the center but still has a slight jiggle when gently shaken—the residual heat will continue cooking it slightly. The top should be lightly golden and the edges may pull away slightly from the crust. Let the quiche cool for 5-10 minutes before slicing; this allows the filling to set completely and makes it easier to serve clean slices.