Preheat the oven to 400F (200C). Line a 12-cavity muffin tin with muffin papers.
In a large bowl, whisk together the flour, sugar, cocoa, baking powder and baking soda.
In a separate large bowl, whisk together the melted butter, oil, eggs, vanilla, vinegar, food coloring, and buttermilk.
Create a well in the middle of the dry ingredients, then pour the wet ingredients into the well.
Using a rubber spatula, carefully fold the wet ingredients into the dry ingredients. It will be a little lumpy, which is expected. Do not overmix, or the muffins will get tough and dry.
When the ingredients look almost combined, fold in the chocolate chips.
Spoon the batter evenly between the 12 muffin papers. They will be filled close to the top.
Bake in the preheated oven for 5 minutes (at 400F). Leaving the muffins in the oven, turn the oven down to 350F (180C). Continue baking for 12-15 minutes, or until an inserted toothpick comes out clean.
Cool the muffins in the pan for at least 5 minutes, then continue cooling on a wire rack. Muffins are best when enjoyed warm from the oven.