Fill a pot with the milk. Stir in salt, if using. Heat over medium heat until milk registers 185°F (85°C) on an instant-read thermometer. Add vinegar or lemon juice and stir briefly to incorporate. Curds should begin forming almost immediately; stop stirring as soon as they've formed throughout the pot. Without stirring, continue to hold curdled-milk mixture at 185°F for 20 minutes. It's okay if the temperature fluctuates down to 175°F (79°C) or up to 190°F (88°C), but try to keep it in that zone for the full 20 minutes.

Line a fine-mesh strainer with paper towels or cheesecloth. Using a slotted spoon, transfer curds to strainer and let stand until excess liquid has drained away (*see recipe notes). Exactly how long to let it drain depends on whether you want a moister final product or a drier one. Do not try to pour all the milky liquid through the strainer, as this will clog it and prevent the liquid from flowing through.

Drained ricotta can be refrigerated, covered, for up to 2 days, though it is best when freshly made.

Heat a pan on medium heat. Add butter. Once butter is melted and hot, add the shallots and cook in translucent. Add the garlic and corn kernels and cook for 5 minutes, stirring. Add the white wine and cook until mostly evaporated. Set sautéd corn aside to cool.

In a food processor, puree the mixture until smooth.

Fold in the ricotta and chill until ready to use.

On a large, clean work surface, pour flour in a mound. Make a well in the center about 4 inches wide. Pour whole eggs, egg yolks, and salt into well and, using a fork, beat thoroughly. When combined, gradually incorporate flour into the eggs until a wet, sticky dough has formed. Using a bench knife, scrape excess dough from fork and fingers. Begin to fold additional flour into the dough with the bench knife, turning the dough roughly 45 degrees each time, until dough feels firm and dry, and can form a craggy-looking ball, 2 to 5 minutes.

Press the heel of your hand into the ball of dough, pushing forward and down. Rotate the ball 45 degrees and repeat. Continue until dough develops a smooth, elastic texture similar to a firm ball of Play-Doh. If dough feels too wet, add flour in 1 teaspoon increments. If dough feels too dry, add water slowly using a spray bottle. Wrap ball of dough tightly in plastic wrap and rest on countertop for 30 minutes.

Meanwhile, place a sheet of parchment paper on a tray or cutting board and dust lightly with flour. Unwrap rested dough and cut into quarters. Set one quarter on work surface and re-wrap remaining dough. With a rolling pin, flatten the quarter of dough into an oblong shape about 1/2 inch thick. Set pasta maker to widest setting and pass dough 3 times through the machine at this setting. Place dough on a lightly floured work surface. Fold both ends in so that they meet at the center of the dough, and then fold the dough in half where the end points meet, trying not to incorporate too much air into the folds. Using rolling pin, flatten dough to 1/2-inch thick. Pass through the rollers 3 additional times. 

Narrow the setting by 1 notch and repeat. Repeat once more (the dough should now have passed through the third widest setting). Continue passing the dough through the rollers, reducing the thickness by 1 setting each time until you reach the thinnest setting. It should now be very delicate and elastic to the touch, and slightly translucent. Place rolled dough onto a work surface or baking sheet lightly dusted with flour or lined with parchment paper; sprinkle with flour.

Fill a piping bag with a 1/2" tip with the corn filling.

Cut your pasta dough into 3" wide strips.

Lay out one strip and pipe filling 1/3 up from the bottom. Fold over the dough and press down, making sure to press tightly against the filling. Pinch the agnolotti (*see recipe notes). Using a ravioli cutter, roll the entire length of the pasta strip where the fold meets. Using the same ravioli cutter, cut the agnolotti where you pinched them off.

Place cut agnolotti on a tray lined with parchment paper. Dust with flour and either place in your refrigerator (if eating with the next two days), or freeze!