Bring pizza dough ball to room temp.
Prepare the caramelized onions. Add olive oil, onions, beef bouillon, and salt to large frying pan. Sauté over medium-low heat for about 30 minutes until onions are golden brown, stirring frequently, adding spoonfuls of water as needed when onions seem dry. Lower the heat if onions start to burn. Continue cooking and stirring until you reach your desired level of caramelization. Add the white wine to the pan, stir well for about 30 seconds or so until the wine is mostly reduced.
Shred the Gruyere and mozzarella cheeses.
In a small bowl, stir together panko, parmesan, and 1 Tbsp olive oil.
Place baking steel on oven rack in lower half of the oven. Preheat the oven and baking steel to 530 degrees F. (Or follow manufacturer guidelines regarding recommended cooking temperatures for your baking steel or baking stone.)
When the dough ball is ready, shape it into 11 to 12 inch round. Shape directly on a wooden pizza peel or board, using flour on the surface as needed so dough does not stick. Once shaped, give the peel a shake to ensure pizza is not sticking, adding some flour underneath the round if there are any sticky spots.
Spoon the caramelized onions onto center of dough round. Use the bottom of a spoon to gently spread the onions into even layer without tearing the dough, leaving about a half-inch at the outer edge.
Scatter the Gruyere and mozzarella over the caramelized onions. Sprinkle dried thyme over cheese.
Transfer pizza onto hot baking steel. Cook for about 7-8 minutes, until edge of pizza is puffed and lightly browned and cheese is starting to brown in spots. Remove pizza from oven. Cool for 10 minutes. Slice in triangles (like a pie) and serve.