For the pretzels: Whisk together the all-purpose flour, bread flour, sugar, yeast and kosher salt in a large bowl or a stand mixer fitted with the dough hook attachment. Stir in the melted butter, egg yolks and warm water, then knead the dough until smooth, 15 to 20 minutes.
Lightly oil the inside of a large bowl, add the dough and brush the top of the dough with some more olive oil. Cover the bowl tightly with plastic wrap, then put in a warm spot, such as the top of the fridge, until the dough has doubled in size, 30 to 40 minutes.
When the dough is almost ready, preheat the oven to 425 degrees F. Line a baking sheet with parchment paper and spray with cooking spray. Place 6 cups water in a wide, shallow saucepan and bring to a simmer over medium-low heat.
Meanwhile, punch down the dough and lightly dust your work surface with flour. Flatten and stretch the dough into a rectangle about 8 inches wide and 12 inches long. Line up 4 pieces of the cheese lengthwise on one half of the dough, spacing them out evenly. Cut the dough in half crosswise and set aside the 8-by-6-inch half without the cheese.
Place a scant tablespoon of the chiles along the top of each piece of cheese. Cut the dough evenly between the pieces of cheese so you end up with 4 rectangles of dough with the cheese in the middle of each. Dab the edges of the dough with a little water. Fold in the ends, then stretch the bottom edge over the center, roll over and seal shut, like a burrito. Repeat with the remaining dough half, cheese and chiles.
When the water is simmering, stir in the baking soda. Working in batches, add the pretzels to the water and cook for 30 seconds, flipping once. Remove using a spider or slotted spoon and shake off any excess liquid, then place on the prepared baking sheet. Brush the top of the pretzels with the melted butter and sprinkle with the pretzel salt.
Using a sharp paring knife, lightly score the top of each pretzel 4 times on the diagonal and bake until browned, 10 to 12 minutes. Set aside until cool to the touch, 5 to 10 minutes. Slice each pretzel crosswise into bite-size pieces. For serving, place the tortilla strips on a platter, top with the pretzel pieces, then layer on the chile salt, pickled jalapeños, Cheddar and scallions.
Never leave a child unattended in the kitchen. Limit the child to tasks that are safe and age-appropriate.