Fill a pot with 1/2" water and bring to a gentle simmer. Add the cauliflower in a steaming basket or rack, cover, and steam until tender, about 10 minutes.
Remove the cauliflower from the pot and allow to cool a bit, then squeeze between paper towels to remove as much water as possible.
Combine everything except olive oil and mayonnaise in a food processor and process until smooth, then shape into 6 patties.
Heat 1 tablespoon olive oil in a skillet over medium heat. Cooking 3 patties at a time (unless your skillet is big enough to cook all of them), cook the patties about 5 minutes on each side, until browned and crispy. Use the remaining 1 tablespoon olive oil for the second batch.
Serve each patty with an optional dollop of mayonnaise.