How to Make It
Preheat the oven to 375°. Using the flat side of a chef’s knife, crush the garlic and 1/2 teaspoon of salt to a paste. Scrape the garlic paste into a medium bowl and add the cream cheese, scallions, egg yolk, cumin, mustard and 1/3 cup of cilantro. Stir with a rubber spatula until well combined. Season with a generous pinch each of salt and pepper, then fold the cheddar into the filling.
On a rimmed baking sheet, toss the jalapeños with the olive oil and a pinch each of salt and pepper until well coated. Arrange them cut side up and spoon 1 1/2 to 2 tablespoons of filling into each one. Bake for about 20 minutes, rotating the sheet from front to back halfway through, until the filling is puffed and bubbling and the jalapeños are tender. Garnish with minced cilantro and serve with lime wedges.