Put the cherries in a medium heatproof bowl. Combine the zest, cherry juice and ½ cup of water in a small saucepan and bring to a boil over high heat (alternately, you can heat in the microwave for 2 minutes). Pour the hot mixture over the cherries, cover with foil or plastic wrap and let sit for at least 30 minutes and up to 24 hours on the counter. Just before adding to the dough, drain the cherries through a fine-mesh strainer into a bowl, then spread them onto a paper towel-lined plate to dry.
Place an oven thermometer directly on the deck of your pizza oven on the right-center side closest to the interior wall of the pizza oven. Turn both burners to the second lowest setting and heat the oven until the temperature on the thermometer reads between 375-400 degrees F, this will take at least 45 minutes.
Whisk the buttermilk and egg together. Set aside. Whisk the flour, granulated sugar, baking soda, salt and fennel seeds together in a large bowl. Cut in the butter using a pastry cutter or your fingers until the butter is pea-sized crumbs. Stir in the cherries and chocolate. Pour in the buttermilk/egg mixture. Gently mix the dough together until the dough is too stiff to stir. Pour crumbly dough onto a lightly floured work surface. With floured hands, work the dough into a ball as best you can, then knead for about 30 seconds or until all the flour is moistened. If the dough is too sticky, add a little more flour (but a moister dough is better for soda bread)
Using floured hands, shape the dough into an 8-inch round that is approximately 2 inches thick. Score the top deeply with a serrated knife before transferring the dough to a seasoned 10–12-inch cast iron skillet or griddle pan. Keep a 12x12-inch piece of foil nearby to cover the top if it starts to brown too quickly.
Bake until the bread is golden brown and center appears cooked through, about 25 minutes, turning the pan several times using heavy duty grill gloves and long tongs, to ensure even baking, Loosely tent the bread with aluminum foil if you notice heavy browning on top. For a more accurate test, the bread is done when an instant read thermometer reads the center of the loaf as 195°F (90°C).
Remove from the oven and allow bread to cool for 10 minutes and then transfer to a wire rack to cool 10 minutes longer. Serve warm, at room temperature, or toasted with desired toppings/spreads.
Cover and store leftover bread at room temperature for up to 2 days or in the refrigerator for up to 1 week.
