Preheat oven to 400 degrees. Line two baking sheets with parchment paper or baking mats. Set aside.
In a medium saucepan, heat butter, sugar, salt, and water together over medium-high heat until it boils. Immediately add all of the flour and stir with a wooden spoon. Continue to stir over heat until a firm forms on the bottom of the pan. Remove from heat and transfer dough to a medium bowl to cool down for 3 minutes.
Once slightly cooled, add 1 egg to dough and stir vigorously until combined into dough. Repeat with rest of eggs, one at a time.
Transfer mixture to a large pastry bag fitted with a large piping tip. Slowly pipe 4-inch logs onto prepared baking sheets. Make sure to space out about 2 inches apart. Dip your finger into water and smooth out the ends of each log of dough.
Gently brush each log with egg wash. Bake eclairs for 30 minutes until they've risen and turn golden brown on top. They should not be foaming on top. If they are, continue baking. Once finished, remove from oven. Poke each eclair with a sharp knife to allow steam to vent. Let them cool completely before filling.
Once the eclairs are cooled and the pastry creme is chilled, it's time to assemble! Place pastry cream in a pastry bag fitted with a small round tip. Using a pairing knife, punch a slit into each end of the eclair. Stuff each slit with the tip of the pastry cream bag and squeeze the pastry cream into the puff until you feel that it's full. Repeat with the rest of the eclairs.
Once all eclairs are filled, heat the heavy cream in the microwave until scalded, about 30 seconds. Add the 10 ounces of melting white chocolate to a small bowl and pour in heavy cream. Do not stir. Let chocolate sit for 10 minutes and then stir until smooth. Dip the tops of each eclair into melted white chocolate and place onto a plate. Sprinkle remaining strawberry powder onto the tops of each eclair. Serve immediately or within 24 hours.