Start by making the strawberry sauce for the filling. Add chopped strawberries, sugar, water, and vanilla extract to a small saucepan.
Bring to a boil, then simmer until the mixture begins to thicken, for about 10 minutes.
Remove the strawberry sauce from heat and transfer into a container. Place it in the fridge and let it cool completely.
To make the churro batter, in a medium saucepan, add the butter, sugar, water, and salt.
Bring it to a boil and let it simmer for 5 minutes.
Turn the heat to low and add in the flour. Stir well with a spatula until it comes together as dough.
Transfer the dough into a stand mixer and mix on low.
Add in the eggs to the dough while mixing. Let it mix for 3 minutes until combined.
Line a baking sheet with parchment paper and sprinkle corn starch on top.
Transfer the dough into a piping bag and pipe into 8-inch churros directly onto the corn starch. Set aside.
To make the filling, combine mascarpone and cream cheese into a medium bowl. Whisk until well combined. Add in the strawberry sauce to the mix until smooth. Transfer into another piping bag and set aside.
Prepare the strawberry sugar by combining dehydrated strawberries and sugar into a food processor and blend until it becomes a fine sugar. Transfer sugar onto a small baking sheet.
Heat up canola oil in a large pot until it reaches 325°.
Fry churros in the oil for about 3 minutes until golden brown.
Remove churros from the oil and roll them into the strawberry sugar until evenly coated.