First preheat the oven to 200 ° top / bottom heat.
Place the baking dish (at least 22 x 22 cm) with the margarine in the oven to melt it.
Meanwhile, mix the remaining ingredients in a bowl and stir until smooth with a mixer. Once the margarine is heated in the oven, pour the batter into the hot casserole dish and return to the oven. The baking time is 18-20 minutes. As soon as the butter has sunk into the batter, the pancake is ready.
You can dust the pancake with powdered sugar or pour maple syrup over it.