The Properties directive allows you to assign AWS::Serverless::Function properties to all Lambda projects or an individual Lambda project. You can also accomplish this under the AwsResources Directive.
Here is an example from the PetStore LazyStack.yaml.
ProjectOptions:
LambdaProjects:
Runtime: dotnetcore3.1
Properties:
MemorySize: 128
Timeout: 30
Tracing: Active
Policies:
- DynamoDBCrudPolicy:
TableName:
Ref: LZDDB01
Environment:
Variables:
TABLE_NAME:
Ref: LZDDB01
TABLE_ARN:
Fn::GetAtt: LZDDB01.Arn