How to Make It
Preheat oven to 375°F. Pulse cream cheese and mayonnaise in a food processor until smooth.
Toss 3⁄4 cup of the Cheddar and 1⁄4 cup of the Monterey Jack with cornstarch in a medium bowl until coated. Stir in cream cheese mixture, salt, and pepper. Spoon into a 1-quart baking dish, and top with remaining 1⁄4 cup each Cheddar and Monterey Jack cheeses.
Bake in preheated oven until golden and bubbling around the edges, about 15 minutes. Remove from oven; sprinkle with Spicy Pecans. Cool 5 minutes; sprinkle with chives. Serve with toasted baguette slices.