Heat the 2 tablespoons olive oil in a pan over medium-high heat.
Add the minced meat, diced onion, and garlic. Fry for 5-7 minutes until the meat is browned, stirring occasionally. Season with thyme, salt, and cayenne pepper.
Drain the corn and add it to the meat mixture.
Wash, quarter, and core the tomatoes. Cut the pulp into small cubes.
Add the tomato cubes and salsa sauce to the meat mixture. Bring to a boil, then simmer for 2 minutes.
Spread about one-third of the meat mixture over the bottom of a large baking dish.
Fill each of the 4 tortillas with the remaining meat mixture and roll up tightly.
Cut each rolled tortilla in half across and arrange seam-side down in the baking dish.
Mix the grated cheese with the crème fraîche or sour cream. Season with the 2 tablespoons lemon juice.
Spread the cheese mixture evenly over the tortilla rolls.
Bake at 175 °C (350 °F) for 30 minutes until the top is golden and the casserole is heated through.