Here's Heston Blumenthal's mushy pea recipe:
Mushy peas
Serves 4-6
475g frozen peas (I like Birds Eye)
65g butter
6 mint leaves
Salt and pepper, to taste
1 Defrost the frozen peas in a large pot filled with cool water — this should take a only few minutes. Strain, shaking off as much excess water as possible.
2 Reserve about one-fifth of the peas.Place the remaining peas into a sauté pan, along with the butter and 50ml water. Cook over a medium heat until all the water has evaporated and the peas are cooked through. If your water is very hard, it would be best to buy some bottled water (or, even better, de-ionized car-battery water) to use when cooking the peas, as this will help to keep their colour bright green.
3 Place the cooked peas into a blender (or use a stick blender) and purée. While blending, adjust the taste by adding the mint leaves and the salt and pepper.
4 Fold in the reserved peas and serve.
http://www.timesonline.co.uk/tol/life_and_style/food_and_drink/heston_blumenthal/article631377.ece