Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.

Cut sweet potatoes into ½-inch-thick wedges.

Toss on a baking sheet with a large drizzle of oil, salt, and pepper. Roast on top rack until browned and tender, 18-20 minutes.

Meanwhile, halve cucumber lengthwise; slice crosswise into 1-inch-thick half-moons. Arrange cucumber pieces across a cutting board; carefully press down with a plate to smash.

Add smashed cucumbers, vinegar, and ½ tsp sugar (1 tsp for 4 servings) to a medium bowl; toss to combine. Season with salt and chili flakes to taste.

Set aside to marinate, stirring occasionally, until ready to serve.

In a small bowl, combine ketchup, ponzu, and ¼ tsp sesame oil (½ tsp for 4 servings). (Be sure to measure the sesame oil—we sent more!) 

Place sourdough slices on a clean work surface. Evenly spread one side of each slice with gochujang aioli or mayonnaise, or a combination of both. TIP: If you like spice, use the gochujang aioli; if you prefer things mild, stick to mayonnaise only!

Evenly top half the sourdough slices with half the mozzarella. Top with kimchi and remaining mozzarella. Top with remaining sourdough slices, aioli or mayonnaise sides down, to form sandwiches. 

Heat 2 TBSP butter (4 TBSP for 4 servings) and a drizzle of oil in a large pan over medium heat. Once hot, add sandwiches. (TIP: Work in batches if necessary, adding more butter if needed.) Cook, gently pressing down with a spatula, until cheese begins to melt and bread is golden brown, 2-4 minutes.

Add another 1 TBSP butter to pan, then flip sandwiches. Cook until cheese fully melts and bread is golden brown, 2-4 minutes more. TIP: Lower heat if sandwiches begin to brown too quickly.

Halve kimchi grilled cheese sandos on a diagonal.

Divide sandos, sweet potato wedges, and smashed cucumber salad (draining first!) between plates in separate sections. Garnish cucumber salad with sesame seeds. Serve with sesame-soy ketchup on the side for dipping.