Set the butter out in advance to soften; no point in starting until it has.
Grease the baking pan, then line it with waxed paper or greaseproof paper. Set aside.
Start heating oven to 175 C / 350 F / Gas Mark 4.
Melt the chocolate in a microwave or on the stove. Set aside to cool a bit.
Cream the butter and half the sugar together. Beat 3 of the eggs in, one at a time. Then stir the chocolate in, then the flour, and spread ¾ of this chocolate mixture over the bottom of the baking pan. Set aside.
In a fresh bowl, mix together the cream cheese, the vanilla, and the final half of the sugar and the remaining 2 eggs. If you have an electric handmixer, you can use it.
Spread all the cream cheese mixture out over the chocolate base. Drop the remaining ¼ of the chocolate mixture onto this by random spoonfuls, then take a fork and just swirl it lightly in.
Press whatever (washed) fruit you are using into various places on the top.
Bake for about ¾ of an hour or until a knife comes out clean. When cool, cut into squares.
Notes
Instead of raspberries, you can use strawberries, blueberries, etc -- any kind of small soft berry that doesn't need sweetening (unlike cranberries or gooseberries).Use anywhere from a few handfuls of berries up to 1 pint / punnet; however many you feel like, really.Use a baking pan that is 13 x 9 x 2 inches (30 x 20 x 3 cm).