Season each troutling with salt and pepper on all sides and inside the cavities as well, then dust with the flour.
Heat 1 tablespoon butter in a cast iron pan over medium-high heat until it begins to brown, then add 1 trout and pan fry on all sides until golden brown, 5-7 minutes, depending on the size of the fish. Just before removing the fish from the pan, toss in 1 tablespoon capers and a healthy squeeze of lemon juice.
Transfer the fish to paper towels. Wipe out the pan and repeat until you’ve pan fried all the trout. I like to serve the fish family-style on a platter with a sprinkling of chopped parsley.