Add the all-purpose flour, semolina flour, and kosher salt to the bowl of a food processor.
Next, add the egg yolks and olive oil and pulse to combine.
With the food processor on low, add the cold water and pulse until the dough forms into a loose ball.
Turn the dough out onto a clean surface and knead just until the dough forms a smooth ball-- about 30 seconds.
Wrap the dough tightly with plastic and set it aside at room temperature to rest for 30 minutes. While the dough rests, make your filling (below).
Lightly flour your work surface with semolina flour and divide the dough in half. Wrap one-half of the dough with plastic and set it aside while you roll the first piece.
Roll your pasta, according to the manufacturer’s instructions, until it is thin enough to see your fingers through the dough.
For a KitchenAid pasta attachment, start on the largest setting (#1) and pass the dough through the rollers. Next, move the roller to one setting smaller (#2) and pass the dough through again. Dust with semolina flour as needed. Repeat until you reach setting #5.
Once the dough is thin enough to see your fingers through, trim it into two equal-sized rectangles.
Pipe your filling onto the dough, making sure to leave enough space to cut your ravioli.
Place one piece of dough on top of the other and press down gently around the filling to remove any air bubbles.
Cut out the ravioli and place them on a semolina-dusted baking sheet.
Repeat steps 7-12 with the second piece of pasta dough.
Once all of the ravioli have been cut, set them aside at room temperature to dry for 30 minutes.
When ready to serve, bring a pot of salted water to a boil and cook the ravioli until they float-- about 2 minutes.
Heat butter and fresh sage in a frying pan over medium heat. When the butter has melted, add the cooked ravioli and toss. Season with salt and pepper, to taste.