Cover the dates with boiling water and leave to soften for 5 minutes. Drain really well.
Blend the dates, cottage cheese, maple syrup and vanilla until smooth.
Add the chia seeds, cocoa and oat flour. Blend until combined, then leave the mixture for 5 minutes to thicken.
If the mixture is still too wet to hold its shape, add more oat flour, one tablespoon at a time.
Press the base firmly into a tin lined with baking paper, smoothing it into an even layer. Refrigerate for 20 minutes.
Melt the dark chocolate, then melt the white chocolate in a separate bowl. Microwave in short bursts, stirring between each until smooth.
Pour the dark chocolate over the base and spread evenly. Add a few dollops of white chocolate while the dark chocolate is still melted, then use a toothpick to swirl them together.
Cut the Maltesers into halves or smaller pieces and scatter over the top, pressing them gently into the chocolate.
Freeze until the chocolate has set and the base is firm. Lift out using the baking paper. Leave at room temperature for 15mins before cutting so the chocolate is less likely to crack.
