Preheat the oven (electric cooker: 250 °C/circulating air: 230 °C/gas: see manufacturer) and line a baking tray with baking paper. Wash, quarter and seed the tomatoes. Dice the flesh finely. Remove the rind from the Gouda, grate roughly.
Cut or pluck the blue cheese into small pieces. Mix everything together. Season with pepper.
Spread the filling over 4 tortillas, leaving an approx. 1 cm wide edge free. Place the remaining tortillas on top. Press on lightly. Spread a thin layer of oil on the surfaces and sprinkle with sea salt. Place 2 quesadillas on the tray.
Bake in a hot oven for about 5 minutes. Bake the rest of the quesadillas in the same way. Cut into pieces. Serve with dips.