Prep Time:	20 min
Cook Time:	3+ hrs

Dry Rub Ingredients (double if cooking 2 racks):

• 6 tbsp (packed) light brown sugar
• 2 tbsp smoked paprika
• 1 tbsp cayenne pepper
• 1 tbsp garlic powder
• 1 1/2 tbsp kosher salt, plus more

• Dry:
  • 1/8 cup (2 tbsp) dry rub spice mixture
• Wet:
  • 1/4 cup (1/2 stick) unsalted butter
  • 1/4 cup apple cider vinegar

• 1 rack of St. Louis style pork ribs, back membrane removed (may be difficult to do, use paper towel to get a hold of the membrane)

1. Cut each full rack of ribs in half.
2. For the rub, combine brown sugar, paprika, cayenne, garlic powder, and 1 1/2 tbsp salt in a bowl; set aside 1/8 cup (2 tbsp) dry rub spice mixture. Pat ribs dry with paper towels and massage spice rub into both sides of ribs. Put ribs on plate and cover with plastic wrap, refrigerate for about 1 hr (can be refrigerated ahead of time for up to 24 hrs).
3. Preheat oven to 300 degrees F (150 degrees C).
4. Seal each half rack in an aluminum foil packet and bake for 2 1/2 hrs.
5. Remove ribs from the oven.
6. Open each foil pakcet and carefull pour juices from ribs into a large heatproof measuring cup. Let juices settle, then spoon fat from surface and discard.
7. Heat butter in a medium saucepan over medium, stirring often, until it foams, then browns (do not burn), 5-8 mins.
8. Add juices from ribs and 1/8 cup reserved dry rub spice mixture and bring to a simmer. Cook until reduced by one-third, 15-20 mins. Remove sauce from heat, add vinegar, and season with salt.
9. Preheat outdoor grill for medium-high heat (about 450 degrees F, not hotter, too much heat will dry out the ribs).
10. Remove racks from the foil, place on grill. Grill ribs for 3-4 mins on each side. Optionally, brush sauce on ribs while they're grilling, just before you serve them (adding it too early will burn it).

Notes:

1. The sauce is best used for dipping. Brushing sauce over ribs while they're grilling can mask the taste of the rub and can make the ribs too soggy; the idea behind grilling them is to crisp up the outside.