In a medium heavy-bottomed saucepan, whisk together the evaporated milk and cornstarch until no lumps remain.

Add the finely shredded cheddar cheese to the saucepan. Place over medium-low heat.

Whisk the mixture constantly as the cheese melts. Continue whisking until the emulsion is smooth and begins to thicken significantly (approximately 5-7 minutes).

Once thickened to a paste-like consistency, remove from heat and stir in the butter, onion powder, garlic powder, and salt until fully incorporated.

Transfer the cheese mixture to a shallow bowl. Press plastic wrap directly onto the surface of the cheese to prevent a skin from forming.

Refrigerate the mixture for at least 1 hour, or until completely chilled and firm.

Transfer the chilled cheese to a food processor. Pulse for 20-30 seconds until the mixture is perfectly smooth and aerated into a creamy spread.

Fill a piping bag fitted with a medium round tip (or a plastic storage bag with the corner snipped) with the cheese filling.

Lay out 48 crackers on a flat surface, bottom-side (flat side) up.

Pipe approximately 1/2 teaspoon of filling onto the center of each cracker.

Place the remaining 48 crackers on top, pressing gently until the filling reaches the edges of the crackers.

Let the sandwiches sit at room temperature for 15 minutes to allow the filling to set and adhere to the crackers before serving.