Preheat the oven to 375 degrees F (190 degrees C).
Cook ground beef, mushrooms, sweet onion, and jalapeno pepper in a large skillet over medium heat until the beef is browned and crumbly and the mushrooms are softened, about 10 minutes. Drain excess grease and stir in ketchup, yellow mustard, salt, and black pepper. Remove from heat.
Roll out pizza dough on a floured work surface and cut dough in half. Spoon half the ground beef onto each dough half; top each with 6 dill pickle slices and half the American-Cheddar cheese blend. Fold dough over to enclose filling and press edges together with a fork to seal the calzones. Place calzones onto a baking sheet, brush tops with olive oil, and sprinkle with sesame seeds.
Bake in the preheated oven until calzones are golden brown and the cheese has melted, 15 to 20 minutes.
