Preheat oven to 350F. Lightly grease and flour a 9-in loaf pan. Set aside. In a large bowl, whisk melted butter, eggs, milk, and vinegar until smooth. Add flour, baking powder, baking soda, salt, and sugar, gently mixing until a smooth batter forms. Fold in cheese and jalapeno.
Scrape batter into prepared pan and smooth top. Bake quick bread at 350F 45-50 minutes or until golden-brown and a toothpick tests done. Cool completely in pan, then transfer to a wire cooling rack. Slice and enjoy!