Pistachio almond lemon rose baklava

Name: Pistachio, almond, lemon & rose baklava
Ingredients: 125g ground almonds; 300g pistachios, chopped in a food processor (some roughly, some finely); 1 lemon, finely zested and juiced, plus 4 broad strips of zest; 500g granulated sugar, plus 3 tbsp; 200g butter, melted, plus extra for the tin; 2 x 250g packs of filo pastry (you won’t use all the sheets); about 2 tsp rosewater (add to taste as brands vary in strength); handful of pink rose petals, unsprayed (optional)