Step 1Combine the milk, flour, eggs and butter in a blender and process until smooth. Strain the batter into a nonreactive container, cover tightly and refrigerate overnight.
Step 2Heat a crepe pan or medium nonstick skillet over medium heat. Lightly grease the pan with a little butter, then pour in one-fourth cup batter, tilting the pan so that the batter forms a roughly 7-inch-diameter circle. Cook until the crepe is just set on the bottom, about 1 1/2 minutes, then flip and cook until set on the other side, about 1 minute more. Adjust the heat as necessary so the crepes do not color too much or cook too quickly. Store the cooked crepes between layers of parchment or waxed paper. The batter makes 8 crepes.
Step 1In a small, heavy-bottom pan, combine the sugar, butter and corn syrup. Place the pan over medium heat, melting the sugar and butter and bringing the contents to a low simmer. Remove the pan from the heat and add the brandy and creme de banana. Place the pan over medium-high heat and cook 1 to 2 minutes to combine the flavors. Reserve and keep warm.
Step 1Place the banana quarters on a pie tin or baking sheet cut-side up. Sprinkle the sugar evenly over the bananas and brulee with the blow torch just until the sugar is caramelized. Reserve.
Step 2Heat the oven to 200 degrees. Spread 1 tablespoon of Nutella over half of each crepe, then fold in half and spread an additional tablespoon of Nutella over the folded crepe. Fold the crepe once more to form a triangle. Repeat with the remaining crepes. Place 2 crepes on each of 4 heat-proof serving plates, or onto a parchment-lined baking sheet, and heat in the oven just until the crepes are warm and the Nutella is soft and creamy. Remove the plates (or remove the crepes, 2 each, to the serving plates) and spoon one-fourth cup of the warm Foster sauce over each serving.
Step 3Garnish each serving with 4 pieces of caramelized banana. Place a scoop of ice cream in the center of each plate and scatter the raspberries evenly over the servings. Garnish each with a mint sprig and a light sprinkling of powdered sugar. Serve immediately.