In a large bowl, whisk egg with steak spice and HP sauce. Crumble in beef. Using your hands or a fork, gently mix together. Shape into 4 burgers, each about 1/2 inch (1 cm) thick.
Lightly coat a large frying pan with oil and set over medium heat. When hot, add burgers. Cook, uncovered, from 5 to 8 minutes per side. Remove to plates.
Melt butter in pan. Add mushrooms. Stir often until lightly browned around edges, 3 minutes. Pour in wine. Bring to a boil over high heat. Stir occasionally until wine is reduced by half, 3 to 5 minutes. Spoon over burgers.
Nutrition (per serving)
This pan-fried version of the classic burger is as juicy and smoky as a big, meaty barbecued steak!