Oven appliance with flame proving

An oven appliance, comprising:

• a cabinet;
• a chamber defined within the cabinet for receipt of food items for cooking, the chamber delineated by a plurality of walls including a bottom wall, a left side wall, and a right side wall;
• a gas burner positioned within the chamber;
• a first temperature sensor positioned proximate the gas burner;
• a second temperature sensor distal from the first temperature sensor and the gas burner, the second temperature sensor positioned and configured to measure a temperature in the chamber;
• and
• a controller positioned within the cabinet, the controller in data communication with the first temperature sensor and the second temperature sensor;
• wherein the controller is configured for:
• measuring a first temperature with the first temperature sensor;
• measuring a second temperature with the second temperature sensor;
• calculating a difference between the first temperature and the second temperature;
• and
• determining a flame is emanating from the gas burner in response to a positive difference between the first temperature and the second temperature.