Preheat your oven to 350°F (175°C). Position an oven rack in the middle position.

Prepare the dry rub by mixing garlic powder, onion powder, paprika, brown sugar, black pepper, and salt in a small bowl until well combined.

Rinse the spareribs and pat them dry with paper towels. Remove the thin membrane from the back of the ribs by sliding a knife under it and pulling it off with a paper towel.

Generously apply the dry rub mixture to both sides of the ribs, massaging it into the meat.

Place the ribs on a large baking sheet, meat side up. Pour water into the bottom of the pan. Cover tightly with aluminum foil.

Bake in the preheated oven for 2 to 2.5 hours, or until the meat begins to pull away from the bones but is not falling off completely.

While the ribs are baking, prepare the BBQ sauce. Combine all sauce ingredients in a medium saucepan over medium heat. Bring to a simmer, then reduce heat to low and cook for 15 minutes, stirring occasionally. The sauce should thicken slightly. Remove from heat and let cool.

Preheat your grill to medium heat (about 350°F).

Remove the ribs from the oven and carefully transfer them to the preheated grill.

Grill the ribs for 10-15 minutes, basting frequently with the BBQ sauce and turning occasionally to prevent burning. The sauce should caramelize and create a sticky, delicious glaze.

Once the ribs are nicely charred and the sauce has formed a glossy coating, remove them from the grill.

Let the ribs rest for 5-10 minutes before cutting between the bones to serve.