Start by adding the roasted coffee beans to a mixer.
Next, cover it with plastic wrap and grind everything very well until it turns into a fine powder.
Now, place a paper filter in a teacup, then add the ground coffee we prepared, the hot water and strain all the coffee.
Remove the filter and set the coffee aside.
In a large saucepan, add the refined sugar, the cornstarch, the milk, the coffee we prepared earlier and mix everything very well until the cornstarch dissolves.
Turn on the heat to medium-low and stir everything until it slightly thickens.
After doing that, transfer all this cream to a baking pan lined with parchment paper and spread it evenly.
Place the dessert in the refrigerator and let it chill for at least 2 hours.
After this time has passed, unmold the dessert and finish with cocoa powder to taste.
Serve.