Make SPG seasoning with equal parts of salt flakes, course ground black pepper and garlic granules.
Lightly oil steak and cover with SPG seasoning.
Set up BBQ for dual zone cooking, for reverse searing method by lighting up half of a chimney starter of fuel. Once fully alight, place in a charcoal basket and add a couple of chunks of unlit lump to just keep the heat going steady. Allow the grill to warm up for 5 to 10 minutes.
(Optional) If using Grill Grates, place them upside down over lit fuel to warm up for the searing part of the cook.
Place steak on cooler side of BBQ and cook at a temp of 200°F to 250°F, add some smoking wood to add another depth of flavour, I used cherry.
While the steak is cooking, prep some mushrooms by placing them in a baking dish along with melted butter, minced garlic, freshly chopped thyme, vinegar, and mix thoroughly, season with kosher salt and black pepper.
Now prep some asparagus, by grabbing either end of each stalk and bending until it snaps. Throw the stalk away and keep the head. Now thread them onto a skewer to make turning them easier.
When the steaks internal temp reaches 100°F, light up another ¾ of charcoal and place mushrooms in the BBQ on the cooler zone.
Once the steak hits 115°F, take it off the heat to rest it and put some butter on it and cover with foil. Add extra fuel to get the temp of 600°F plus ready for the searing of the steak.
Use this extra heat to grill the asparagus on the grill grates, 3 to 4 minutes per side is ample.
Once the asparagus is charred up, take it off the skewer and drizzle with olive oil and a good pinch of kosher salt and black pepper and place on the cooler zone of the BBQ to keep warm.
Start searing the steak. Keep flipping the steak after each minute and monitor the internal temp with an instant read thermometer. Aim for 130°F internally for a perfect medium rare steak.
Once the steak is ready, remove all from heat and serve immediately with the mushrooms and asparagus.