Sprinkle the gelatin in 1/2 cup water. Let stand about 2 minutes to soften. Microwave on high for 45 seconds. Stir for 15 seconds, until the gelatin is dissolved.
In a 2-quart saucepan, heat the evaporated milk until hot, making sure not to boil. Whisk in the cajeta until smooth and evenly incorporated. Stir in the gelatin mixture to the cajeta mixture and turn the heat off to cool slightly.
In a large mixing bowl, using a hand mixer, or in the bowl of a stand mixer fitted with the whisk attachment, add the cream cheese and beat on medium speed while slowly adding 1/3 cup of the cajeta cream to temper the cream cheese and avoid curdling or separation. Gradually add the remaining cajeta cream and continue beating until smooth. Scrape down the sides and bottom of the bowl and beat again until fully incorporated and frothy. Strain the cream into a glass pitcher or into a 4-cup liquid measure, maintaining as much froth as possible. Pour 1 cup of the cream into each of the 4 wine glasses.
Garnish with 3 to 5 fresh raspberries (the raspberries will remain afloat in the froth). Cover with plastic wrap and refrigerate for 8 hours or overnight.