Optional additions (if not too strict about added sweeteners)
1tablespoonWorcestershire sauce(adds great kick)
2tablespoonshoney, Maple Syrup, or Molasses (or a combination of 2-3 of these)
In a large pot set to medium heat melt 1 tablespoon butter and 1 tablespoon olive oil and add the onions. Stir occasionally until the onions are soft (golden/starting to caramelize), and sweet to the taste (at least 20 minutes). *you may need to adjust the heat and turn it down if they are browning too fast.
Next add the garlic and jalapeño and stir together for 2 minutes.
Add remaining ingredients and bring to a simmer. Cook for 15-20 minutes, or until the mango cubes have softened.
Using a hand immersion blender, or countertop blender, blend your sauce until smooth and there are no chunks.
Taste and adjust seasonings to your preference. If too thick add water or more apple cider vinegar. If you’re flexible on sweetness, add some sweeteners (honey, maple syrup, etc. to your taste preferences).
Make sure to read your labels. Many tomato sauces have added sugar. Make sure to use a brand that does not add any sugar. Same with the Worcestershire sauce. Many of them contain added sugar.