Preheat oven to 425°F. Combine milk, water, butter, and salt in a saucepan and bring to a boil over high heat. Mix flour and sugar together and add to saucepan, continuously stir with a wooden spoon until dough forms, coming away from sides of pan. Lower heat to medium and cook dough until slightly shiny and forms a ball, about 2 minutes.

Transfer dough to a mixing bowl of a stand mixer. Start mixing on low speed for 3-4 minutes until slightly cooled. Start adding eggs in one at a time making sure each one is fully incorporated before adding the next one. Beat for 1 minute after all eggs are added.

Prepare your baking sheet lined with parchment paper. Transfer dough into a piping bag with a 1.5 cm piping tip. Pipe strips of dough 2 cm wide by 8cm long. Place tray in oven and bake for 15 minutes then reduce temperature to 350°F and bake for 18-20 minutes longer or until golden brown and when split in half they are almost dry inside. Remove from oven and poke a hole in each end of the éclairs to let the steam escape. Cool completely before filling.

Begin making your filling by mixing the icing sugar and cornstarch together, set aside. Pour whipping cream and raspberry extract into a mixing bowl of stand mixer fitted with a whisk attachment. Whip cream until soft peaks form; gradually add in icing sugar mixture and continue to beat until stiff peaks form. Transfer mixture into piping bag fitted with a star piping tip and keep in fridge until ready to use.

To fill the éclairs, cut along one long side of the éclair, being careful not to cut right through to the other side. Gently open it up to allow room to pipe your whipped cream filling in. Repeat and fill all éclairs. Alternately, instead of cutting open éclairs you can fill them by piping into the holes on each end.

To make white chocolate glaze, place all ingredients (except the icing sugar) in microwave safe bowl, heat in 15-second intervals on high, stirring after each duration until chocolate is melted, 30 seconds total. Continue to stir until smooth and chocolate has melted completely. Gradually add in half of the icing sugar, stir until smooth, then add the rest, repeat until smooth consistency. Spoon glaze over assembled éclairs, spreading gently to allow glaze to cover tops.

Best served immediately or stored in airtight container in refrigerator for up to 2 days. Allow to come to room temperature before serving.