In a large pot, heat up one cup of water with butter, oil, sugar and salt. Bring water to boil over medium heat.
Add flour to boiling water, stir vigorously with spatula until mixture comes together and is smooth. turn of heat.
Transfer the flour mixture to a large mixing bowl and let it cool down to touch - about 7-8 minutes.
Add eggs one at a time to the flour mixture and blend immediately with an electric mixer.
Blend until the mixture comes together and is smooth. It will be separate at first but it will come together. Just keep mixing it.
Transfer the dough in the piping bag fitted with large star nozzle.
Heat oil in a big dutch oven or a large pot over medium to high heat. Meanwhile prepare the coating by mixing sugar and cinnamon in a shallow dish and set aside.
Carefully, pipe the mixture into preheated oil, about 4-5 inches long, cut with scissor or knife.
Let it fry for couple of minutes on each side until golden brown.
Transfer to paper towels to dry and pad it down extra oil lightly.
Coat the cinnamon sugar over the fried churros.
Repeat the process with the remaining dough.
Serve warm with nutella or chocolate sauce for dipping and enjoy!