Fish with White Wine Sauce and a Pea Puree

Name: Fish with White Wine Sauce and a Pea Puree
Yield: 2 servings
Ingredients: 0.5 medium, finely diced Onion; 1 cup White wine (dry (I used Chardonnay)); 1 tsp Lemon juice; Salt (to taste); Pepper (to taste); 1 cup Cream ((In some countries it's double or heavy cream)); 0.015 15g / 1 tbsp Butter (Small cubes); 0.5 kg Frozen peas; 0.07 70g / 5 tbsp Butter; 2 Garlic cloves (minced); 1 medium, thinly sliced Onion; 0.75 cup Chicken or vegetable stock/broth; 0.25 tsp Salt; 0.125 tsp White pepper; 2 200g / 7oz Fish fillets (skinless, boneless (I used Pollock. Hake, Cod, King Kilp would also be great)); Salt & Pepper; 1 1-2 tbsp Olive oil