For Pizza Crust:
Allow enough time for dough to thaw according to package directions.
When thawed, smash each loaf into a ball, then roll into a 16-inch circle to form pizza crusts.
For the steak:
Heat grill to high. Brush steak on both sides with olive oil and season with salt and pepper. Sear steak on hot grill until you see char marks on both sides, about 2-3 minutes per side.
Brush seared steak with 2 tablespoons of balsamic glaze and continue grilling and turning, until cooked to medium-rare doneness, about a total of 5 minutes per side or 140 degrees internal temperature.
Remove steak from the grill to a cutting board, tent loosely with foil and let rest for 10 minutes.
Slice into 1/4-inch thick slices.
For the pizza:
Heat the grill to high.
Brush both sides of the pizza dough with olive oil and season with salt and pepper.
Grill until golden brown on both sides, about 2 minutes per side.
Remove from the grill.
Divide Fontina cheese into fourths. Add 1/4 of the Fontina cheese onto each pizza crust.
Divide washed, dried and chopped spinach, and place evenly on top of each pizza crust.
Top with remaining Fontina cheese and sprinkle with crumbled blue cheese and fresh thyme.
Place topped pizzas back onto the grill, close the cover, and grill until the cheese has melted, about 1-2 minutes.
Remove to a flat surface, divide the steak between each pizza.
Drizzle with some of the balsamic glaze, slice and serve immediately.