Wash and dry produce.

In a medium bowl, combine coleslaw mix, mayonnaise, half the vinegar, and 1 tsp sugar (all the vinegar and 2 tsp sugar for 4 servings). Taste and season with salt and pepper.

Set aside, stirring occasionally, until ready to serve.

Evenly spread half the sourdough slices with mustard; evenly top with ham and gouda. Top with remaining sourdough slices to form sandwiches.

Heat ½ TBSP butter and a drizzle of oil in a large pan over medium heat. Once butter has melted, add sandwiches, bread with cheese sides down. Push sandwiches around pan until butter and oil has absorbed. Cover and cook until bread is golden brown on one side and cheese begins to melt, 4-6 minutes.

Add another ½ TBSP butter and drizzle of oil to pan and flip sandwiches. Push sandwiches around pan until butter and oil has absorbed. Cover and cook until bread is golden brown on second side and cheese melts, 4-6 minutes. (For 4 servings, work in batches or use a second pan, wiping out pan between batches and adding ½ TBSP butter and a drizzle of oil for each side.)

Halve melts on a diagonal.

Divide melts and coleslaw between plates. Serve.