3. Brownie layer a. Melt the chocolate and butter. This is best done in a bowl over a saucepan of simmering water. b. Sieve the flour and cocoa and mix together in a bowl with the caster sugar. c. Beat the eggs together in a separate bowl. d. Once the chocolate and butter have melted, pour them into the bowl and mix well. Beat in the egg once combined. 4. Pour the brownie mix into the tin. 5. Cover the brownie mix with oreos. Lightly press them in to the mix.