Step 1

This  dip  is best served warm. Serve with crackers or a thinly sliced baguette.

Step 2

FOR THE TOPPING: Pulse the bread in a food processor to coarse crumbs, about 6 pulses. Toss the bread crumbs with the Parmesan and butter; set aside.

Step 3

FOR THE DIP: Adjust an oven rack to the middle position and heat the oven to 450 degrees. Line a baking sheet with foil. Toss the artichokes with 1 tablespoon of the oil, 1/2 teaspoon salt, and 1/4 teaspoon pepper, and spread out over the prepared baking sheet. Roast the artichokes, stirring occasionally, until browned at the edges, about 25 minutes. Let the artichokes cool and then chop coarse.

Step 4

Meanwhile, heat the remaining 1 tablespoon oil in a 10-inch skillet over medium-high heat until just shimmering. Add the onion and cook until softened, 5 to 7 minutes. Stir in the garlic and cook until fragrant, about 30 seconds. Transfer the onion mixture to a large bowl and set aside.

Step 5

Stir the mayonnaise, cream cheese, Parmesan, lemon juice, thyme, and cayenne into the onion mixture until uniform, smearing any lumps of cream cheese against the side of the bowl with a rubber spatula. Gently fold in the chopped artichokes and season the mixture with salt and pepper to taste. Transfer the mixture to an ungreased 8-inch square baking dish and smooth the top. Sprinkle the bread crumbs evenly over the top.

Step 6

TO STORE: Cover the baking dish tightly with plastic wrap and refrigerate for up to 3 days.

Step 7

TO SERVE: Adjust an oven rack to the middle position and heat the oven to 400 degrees. Unwrap the dip and bake, uncovered, until hot throughout and the bread crumbs are golden brown, 20 to 25 minutes. Let cool for 5 minutes before serving.