New Haven-Style White Clam and Garlic Pizza
from http://www.weber.com/, modified

This recipe comes from Weber's web site and is cooked on the grill. It could just as easily be baked in the oven.

See below for Meathead's recipe from https://amazingribs.com/.

FMM: We made this and it wasn’t too bad. I put just a little bit of hot pepper flakes on once it came out of the oven and it overpowered the flavor of the clams. I had a whole can of clams on top and mixed clam juice with the olive oil that was brushed on top. I thought maybe making a topping using the Linguine with Clam Sauce made with clam juice and wine as inspiration, would bring the clam flavor out better, sort of like the Shrimp Scampi pizza we make (where we make a garlic sauce and top with Shrimp Scampi), which is really good. I found a recipe on the Internet that looked similar to what I had in mind. See White Clam Sauce Pizza With Chili Oil.

2 cans (each 6½ ounces) chopped clams
1 tablespoon clam juice (from the can of chopped clams)
1/4 cup extra-virgin olive oil
2 teaspoons minced garlic
2/3 cups finely chopped fresh Italian parsley leaves
1/2 cup freshly grated Parmigiano-Reggiano® cheese
2 teaspoons dried oregano
Finely grated zest of 1 lemon
Kosher salt
Freshly ground black pepper
Parchment paper
2 rounds of pizza dough
Crushed red pepper, for serving [do not sprinkle on before baking]

Prepare the grill for direct cooking over medium heat (350° to 450°F).

Roll or press each piece of pizza dough into an approximate circle, 8 to 9 inches wide and about 1/4 inch thick (don't worry if it's not exact; irregular shapes are fine). Oil two 12-inch squares of wax paper or parchment paper and place one dough round on each.

Drain the clams and reserve 1 tablespoon of the clam juice. In a small bowl whisk the 1/4 cup oil, garlic, and the reserved 1 tablespoon clam juice. In another bowl combine the parsley, cheese, oregano, and lemon zest. Put the drained clams in a third bowl.

Brush the cooking grates clean. Place the dough on the cooking grate with the paper side facing up. Grill over direct medium heat, with the lid closed as much as possible, until the dough is well marked and firm on the underside, 2 to 4 minutes, rotating as needed for even cooking (don't worry if the dough bubbles). Remove and discard the paper.

[You can bake the pizzas in a 450 degree oven. Don't bake the crust first, then flip over. Parbake the crust for a few minutes without toppings to set the crust a bit, then bake as you would any other oven pizza. See the recipe for Pizza Dough.]

Turn the dough over and brush the tops with the oil mixture (be certain to use all of it). Distribute the minced garlic evenly over the dough. Working quickly, add the clams and then top with the parsley-cheese mixture. Close the lid and continue to cook until the cheese melts and the crusts are crisp, 2 to 5 minutes more. Remove the pizzas from the grill and season with salt and pepper. Cut into wedges and serve right away with crushed red pepper on the side.

Makes two pizzas

Meathead's Recipe for Frank Pepe's White Clam Pizza
from https://amazingribs.com/

The white clam pizza, a New Haven, Connecticut specialty, is credited to Frank Pepe of Frank Pepe Pizzeria Napoletana. He is said to have invented it in the mid-1960s by topping a thin-crust pizza with fresh clams, grated cheese, olive oil, garlic, and oregano. The Pepe's website describes the pizz this way: Fresh Clam, Garlic, Oregano, Grated Pecorino Romano & Olive Oil.

About the clams. Pepe’s uses whole, live fresh Littleneck clams from Rhode Island and shucks them on site. You can do this too, but it is a lot easier to get pre-shucked fresh or fresh frozen clam meats. Whole shucked clams cook at about the same rate as the crust, but if you can only find chopped clams, they’ll do, they just be a little chewier. I’d advise against minced clams because they are so small and will get rubbery. Canned whole clams are cooked in the canning process and have an inferior flavor and they can be very chewy, but in a pinch, they work.

Meathead's recipe:
16 ounces Roman style pizza crust, for 12" pizza
36 raw Littleneck clam meats
1/2 cup freshly grated real Italian Pecorino Romano cheese
2 cloves garlic, peeled and minced fine
4 tablespoons extra virgin olive oil
2 tablespoons dried oregano

Add the toppings. Pat the clams dry and place them on the dough, spreading them out evenly, and take them to within 1" (2.5 cm) of the edge. Then sprinkle on the garlic, cheese, oregano, and finally drizzle on the oil. The oil will pool but don't worry, it will spread out in the oven. I like to take a brush and paint a little oil on the edges of the dough.

Cook. Bake until the dough on top and the bottom is tan to golden.

Make 1 12" pizza

FMM: I only had a 10" crust, so reduced the ingredient amounts. I used canned clams, only about 1/3 of the can, but there were still plenty on top. Even with using less of the other ingredients, there was plenty of garlic. I did not use the total amount of cheese, as what I did use was covering the whole pizza, Same with the oregano. I thought putting more on would be overpowering. Used 3 tablespoons of olive oil to wet the cheese. I only had pre-grated cheese, not freshly grated.
The pizza wasn't too bad, but I would cut back on the cheese, especially if pre-grated as it is finer. While good tasting, it was salty. Next time I won't use as much oregano. I think you need a good sprinkling and that is it. I could have used a little less garlic, but do think it is a key flavor. The oil was needed to help moisten the cheese, but it was a bit oily. Next time I will use fresh cheese and grate it myself.