Microwave Raspberry Sponge in a Plastic Pan

I've never made a cake in the microwave before, but I foresee I will be making more. I made this from ingredients I had in to use them up and it turned out so well I am recording the recipe since I heavily adapted it from a number that I found.  These are the amounts I used:

Ingredients

2.6 oz butter (all that was left of a packet - out of date)
2.6 oz caster sugar (ie same as butter)
2.6 oz SR flour - wholemeal best before March 2013
1.5 oz ground almonds - use by last week - was aiming for 1.3 oz but slipped
0.5 tsp baking powder (just in case SR flour had no R left)
1 med egg
Bit of milk
6.2 oz raspberries (picked last night, washed and left in fridge) with teaspoon of sugar

Method

1 Put raspberries in plastic microwave pan and mashed down a bit with potato masher and sprinkled in sugar and stirred that in a bit.

2 Softened butter by cutting up and putting in warm water then draining off warm water. Added sugar. Beat with electric whisk.

3 Mixed together flour, almonds and baking powder. 

4 Beat egg in a cup. 

5 Added egg and flour mix into bowl with butter/sugar and mixed more with electric whisk.  Added a bit more milk to get to right consistency (soft dropping).

6 Spooned mix onto fruit in the pan.

7 Cooked in microwave on high for 5 mins (= 3+1+1 as wasn't really sure how long - that seemed to be ready, solid sponge come away from the sides a bit).  Put lid of pan on to start but then sponge rose and lifted it so took it off mid way through the cooking.

If I was doing it again.

I'd probably use a bit less fruit and not add any sugar to it.  Should work with other berries.
Would perhaps go for 2.5 oz of each thing that's at 2.6 oz, so slightly less sponge mix for that size pan (felt a bit scary when rising as might go over top of pan)
Maybe add cinamon to the dry ingredients or vanilla?
Maybe not need baking powder if SR flour within date, could of course use white instead of wholemeal.

Worth trying with jams and syrup but maybe syrup would explode?

Verdict

Taste 5 stars
Ease of make 5 stars