In a medium bowl, whisk together 1 cup of the flour with the salt, paprika, Old Bay, cumin, black pepper and cayenne pepper.
In a large bowl, mix together the beer, buttermilk and egg.
Slowly mix the dry ingredients into the wet ingredients and whisk well to break up clumps.
In a large saucepan set over medium-high heat, heat the oil until it reaches 350° on a deep-fry thermometer.
Prepare the petals: Using your fingers, break apart the layers of onion. In a small bowl, combine the remaining cup of flour and the onion pieces. Toss to coat well and shake off any excess flour. Transfer the onions to the bowl filled with batter and coat well.
Working in batches, add the petals to the oil, making sure not to overcrowd the saucepan. Cook until the petals are golden brown and crispy, about 8 minutes. Strain and transfer to a paper-towel-lined plate. Season with salt and pepper. Serve immediately.