Preheat the oven to 425F/218C and line a large baking sheet with parchment paper or a silicon mat. Prepare a large pastry bag tipped with a simple star tip, I used an open french star tip size 8. Place the butter into a medium-sized saucepan and melt it over medium heat. Add the water and salt to the melted butter and allow the mixture to come to a simmer. Add the flour in all at once and whisk for about 20 seconds, until a dough ball forms. Switch over to a spatula and continue mixing and pressing the dough for about 30 seconds.
Allow the dough to cool for about 20 minutes, until it's just lukewarm to touch. Begin adding the eggs, one at a time, mixing well after each addition; do this with a hand whisk or hand-held mixer. The dough will look funny at first but keep mixing; it will come together after the last egg is added. Transfer the dough into the prepared pastry bag. Pipe 4 to 6-inch eclairs onto the prepared baking sheet, spacing them about 1-inch apart. Watch my video recipe to see how it's done.
Bake the eclairs in the preheated oven at 425F/218C for 10 minutes, then reduce the heat to 375F/190C and continue baking for another 40 to 45 minutes, until the eclairs are a deep, golden color. Do not open the oven door at any time during the baking process, otherwise the pastries will fall flat! Remove the eclairs from the oven and let them cool completely. Once cooled, use a wooden dowel or chopstick and create holes for the filling: make 3 holes from the bottom evenly spaced apart, or make 2 holes on either side of the eclairs. Watch my video recipe to see how it's done.
For the Filling:
Next, prepare the peppermint whipped cream filling. First, place the softened butter and cream cheese into a mixer bowl and whisk for 3 to 4 minutes, until the mixture is smooth and creamy. Next, add in the sweetened condensed milk and mix again for a few more minutes until creamy. Scrape down the sides of the mixing bowl often to get everything incorporated.
Add in the chilled heavy cream next, along with the vanilla and peppermint oil. (If desired, add the optional 1 cup confectioner's sugar here for a sweeter filling.) Mix for 30 seconds, stop to scrape down the mixing bowl, then mix on high speed for 3 to 4 minutes, until stiff peaks form. Do not overmix the frosting, as overmixing will cause it to separate!
Assembling the Eclairs:
Transfer the frosting into a pastry bag tipped with a filling tip; I used Wilton Filling Tip #230. Fill the eclairs through the holes created earlier, filling them completely until cream comes out the ends. You will feel the éclair expanding as it fills. Clean up any excess cream.
For garnishing the eclairs, melted the white chocolate melts in the microwave or on the stove top over a double boiler. Dip the eclairs into the chocolate, swirl off any excess chocolate and set onto a wire rack to set. Dip about 3 to 4 at a time and add the crushed candy before the chocolate starts to set. I went with soft candy cane melts. Just place them into a large bag and use a meat mallet or rolling pin and crush them into small pieces.
For the second decorating option, reserve 1 cup of the whipped cream and add red food coloring. Transfer the cream into a pastry bag tipped with a petal tip; I used the Wilton petal tip #104. Pipe the frosting over the top of plain eclairs, then garnish with crushed candy canes. Watch my video recipe to see how it's done.
Keep the eclairs refrigerated if not enjoying within a few hours. Place them into an airtight container; they are best enjoyed within 2 to 3 days.