Preheat the oven to 180°C (350°F) and grease an 8-inch (19cm) iron skillet with vegan butter. Set aside.
To a mixing bowl, add vegan butter, white cane sugar, and brown sugar and cream together with a hand mixer (or use a stand mixer) for about 1 minute until fluffy. Add unsweetened almond milk and vanilla extract and mix until combine. Then add cornstarch, baking soda, sea salt, and half of the all-purpose flour, mix, add the rest of the flour, and mix again with a hand mixer until just combined. Don't overmix the batter. Add chopped dark chocolate bar and pretzels (crush or whole) and mix them in.
Put the dough into the prepared skillet and press it to the sides to make it even. Add additional chocolate chunks and pretzels on the top.
Bake in a preheated oven for about 15 minutes until the cookie is golden brown on the top.
Let the cookie cool slightly before serving.
Enjoy with a scoop of vegan ice cream or coconut whipped cream.