Sauté the following in a splash of olive oil:
7 large jalapeños, sliced. (more or less depending on preference - this makes a medium-hot sauce, as hot sauces go, depending on just how wicked your particular peppers are, and how calloused your taste buds)
3 medium tomatillos, sliced
3 cloves of garlic, sliced
1 clove of shallot, sliced
1/4 onion, diced
While the mixture is heating up, add the following:
juice of about 20 key limes
pinch of coarse-grained salt
punch of sugar
Let that simmer for about 10-15 minutes, stirring occasionally. When done add the entire mixture to your blender along with:
1/2 cup white vinegar
splash of 100% agave tequila
handful cilantro leaves
Blend vigorously until pureed (or use the "Sauce" button on your Blendtec, like I did).
Use as a garnish on your favorite foods. Stores for up to 6 months in the refrigerator.
Update: After further taste-testing and deliberation I think I would up the jalapeño count slightly and reduce the amount of lime juice. YMMV.